diff --git a/progs/demos/geartrain.c b/progs/demos/geartrain.c
new file mode 100644
index 0000000..7e2fea2
--- /dev/null
+++ b/progs/demos/geartrain.c
@@ -0,0 +1,1036 @@
+/* $Id: geartrain.c,v 1.1 2000/03/06 23:34:42 brianp Exp $ */
+
+/*
+ * Geartrain simulation 
+ *
+ * Contributed by Shobhan Kumar Dutta <skdutta@del3.vsnl.net.in>
+ */
+
+
+#include <math.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+#include <string.h>
+#include <stdio.h>
+
+#define min(x, y) ( x < y ? x : y )
+
+#ifndef M_PI
+#define M_PI 3.14159265
+#endif	/*  */
+typedef GLfloat TDA[3];
+
+TDA background;
+
+
+struct AXLE 
+  {
+    char name[20];
+      GLint id;
+      GLfloat radius;
+      GLint axis;
+      TDA color;
+      TDA position;
+      GLfloat length;
+      GLint motored;
+      GLfloat angular_velocity;
+      GLint direction;
+  };
+
+
+struct GEAR 
+  {
+    char name[20];
+    char type[7];
+      GLint face;
+      GLint id;
+      GLfloat radius;
+      GLfloat width;
+      GLint teeth;
+      GLfloat tooth_depth;
+      GLfloat angle;
+      GLfloat angular_velocity;
+      TDA color;
+      GLint relative_position;
+      TDA position;
+    char axle_name[20];
+      GLint axis;
+      GLint direction;
+      GLint motored;
+  };
+
+
+struct BELT 
+  {
+    char name[20];
+      GLint id;
+    char gear1_name[20];
+    char gear2_name[20];
+  };
+
+
+FILE * mainfile;
+struct GEAR g[10];
+struct AXLE a[10];
+struct BELT b[10];
+int number_of_gears;
+int number_of_axles;
+int number_of_belts;
+
+
+char Buf1[256], Buf2[256], Buf3[256], Buf4[256], Buf5[256];
+
+
+void 
+strset (char buf[], char ch) 
+{
+    int i;
+    for (i = 0; i < strlen (buf); i++)
+      buf[i] = ch;
+}
+
+
+void 
+Clear_Buffers () 
+{
+    strset (Buf1, 0);
+    strset (Buf2, 0);
+    strset (Buf3, 0);
+    strset (Buf4, 0);
+    strset (Buf5, 0);
+}
+
+
+void 
+LoadTriplet (TDA A) 
+{
+    Clear_Buffers ();
+    fscanf (mainfile, "%s %s %s %s", Buf1, Buf2, Buf3, Buf4);
+    A[0] = atof (Buf2);
+    A[1] = atof (Buf3);
+    A[2] = atof (Buf4);
+}
+
+
+void 
+LoadReal (float *a) 
+{
+    Clear_Buffers ();
+    fscanf (mainfile, "%s %s", Buf1, Buf2);
+    *a = atof (Buf2);
+}
+
+
+void 
+LoadInteger (int *a) 
+{
+    Clear_Buffers ();
+    fscanf (mainfile, "%s %s", Buf1, Buf2);
+    *a = atoi (Buf2);
+}
+
+
+void 
+LoadText (char *a) 
+{
+    Clear_Buffers ();
+    fscanf (mainfile, "%s %s", Buf1, Buf2);
+    strcpy (a, Buf2);
+}
+
+
+void 
+getdata (char filename[]) 
+{
+    int gear_count = 0, axle_count = 0, belt_count = 0, i;
+    
+    mainfile = fopen (filename, "r");
+    do
+    {
+	Clear_Buffers ();
+	fscanf (mainfile, "%s", Buf1);
+	if (ferror (mainfile))
+	{
+	    printf ("\nError opening file !\n");
+	    exit (1);
+	}
+
+	if (!(strcmp (Buf1, "BACKGROUND")))
+	  LoadTriplet (background);
+      
+	if (!(strcmp (Buf1, "ANAME")))
+	{
+	    LoadText (a[axle_count].name);
+	    axle_count++;
+	}
+      
+	if (!(strcmp (Buf1, "ARADIUS")))
+	  LoadReal (&a[axle_count - 1].radius);
+      
+	if (!(strcmp (Buf1, "AAXIS")))
+	  LoadInteger (&a[axle_count - 1].axis);
+      
+	if (!(strcmp (Buf1, "ACOLOR")))
+	  LoadTriplet (a[axle_count - 1].color);
+      
+	if (!(strcmp (Buf1, "APOSITION")))
+	  LoadTriplet (a[axle_count - 1].position);
+      
+	if (!(strcmp (Buf1, "ALENGTH")))
+	  LoadReal (&a[axle_count - 1].length);
+      
+	if (!(strcmp (Buf1, "AMOTORED")))
+	  LoadInteger (&a[axle_count - 1].motored);
+      
+	if (!(strcmp (Buf1, "AANGULARVELOCITY")))
+	  LoadReal (&a[axle_count - 1].angular_velocity);
+      
+	if (!(strcmp (Buf1, "ADIRECTION")))
+	  LoadInteger (&a[axle_count - 1].direction);
+      
+	if (!(strcmp (Buf1, "GNAME")))
+	{
+	    LoadText (g[gear_count].name);
+	    gear_count++;
+	}
+      
+	if (!(strcmp (Buf1, "GTYPE")))
+	  LoadText (g[gear_count - 1].type);
+      
+	if (!(strcmp (Buf1, "GFACE")))
+	  LoadInteger (&g[gear_count - 1].face);
+      
+	if (!(strcmp (Buf1, "GRADIUS")))
+	  LoadReal (&g[gear_count - 1].radius);
+      
+	if (!(strcmp (Buf1, "GWIDTH")))
+	  LoadReal (&g[gear_count - 1].width);
+      
+	if (!(strcmp (Buf1, "GTEETH")))
+	  LoadInteger (&g[gear_count - 1].teeth);
+      
+	if (!(strcmp (Buf1, "GTOOTHDEPTH")))
+	  LoadReal (&g[gear_count - 1].tooth_depth);
+      
+	if (!(strcmp (Buf1, "GCOLOR")))
+	  LoadTriplet (g[gear_count - 1].color);
+      
+	if (!(strcmp (Buf1, "GAXLE")))
+	  LoadText (g[gear_count - 1].axle_name);
+      
+	if (!(strcmp (Buf1, "GPOSITION")))
+	  LoadInteger (&g[gear_count - 1].relative_position);
+      
+	if (!(strcmp (Buf1, "BELTNAME")))
+	{
+	    LoadText (b[belt_count].name);
+	    belt_count++;
+	}
+      
+	if (!(strcmp (Buf1, "GEAR1NAME")))
+	  LoadText (b[belt_count - 1].gear1_name);
+      
+	if (!(strcmp (Buf1, "GEAR2NAME")))
+	  LoadText (b[belt_count - 1].gear2_name);
+    }
+  
+    while (Buf1[0] != 0);
+  
+    for (i = 0; i < number_of_gears; i++)
+    {
+	g[i].axis = -1;
+	g[i].direction = 0;
+	g[i].angular_velocity = 0.0;
+    }
+  
+    number_of_gears = gear_count;
+    number_of_axles = axle_count;
+    number_of_belts = belt_count;
+    fclose (mainfile);
+}
+
+
+static void 
+axle (GLint j, GLfloat radius, GLfloat length) 
+{
+    GLfloat angle, rad, incr = 10.0 * M_PI / 180.0;
+    GLint indexes[3] =
+    {
+       0, 0, 0
+    };
+    
+    /* draw main cylinder */ 
+    glBegin (GL_QUADS);
+    for (angle = 0.0; angle < 360.0; angle += 5.0)
+    {
+	rad = angle * M_PI / 180.0;
+	glNormal3f (cos (rad), sin (rad), 0.0);
+	glVertex3f (radius * cos (rad), radius * sin (rad), length / 2);
+	glVertex3f (radius * cos (rad), radius * sin (rad), -length / 2);
+	glVertex3f (radius * cos (rad + incr), radius * sin (rad + incr), -length / 2);
+	glVertex3f (radius * cos (rad + incr), radius * sin (rad + incr), length / 2);
+    }
+    glEnd ();
+  
+    /* draw front face */ 
+    glNormal3f (0.0, 0.0, 1.0);
+    glBegin (GL_TRIANGLES);
+    for (angle = 0.0; angle < 360.0; angle += 5.0)
+    {
+	rad = angle * M_PI / 180.0;
+	glVertex3f (0.0, 0.0, length / 2);
+      	glVertex3f (radius * cos (rad), radius * sin (rad), length / 2);
+	glVertex3f (radius * cos (rad + incr), radius * sin (rad + incr), length / 2);
+	glVertex3f (0.0, 0.0, length / 2);
+    }
+    glEnd ();
+    
+    /* draw back face */ 
+    glNormal3f (0.0, 0.0, -1.0);
+    glBegin (GL_TRIANGLES);
+    for (angle = 0.0; angle <= 360.0; angle += 5.0)
+    {
+	rad = angle * M_PI / 180.0;
+	glVertex3f (0.0, 0.0, -length / 2);
+	glVertex3f (radius * cos (rad), radius * sin (rad), -length / 2);
+	glVertex3f (radius * cos (rad + incr), radius * sin (rad + incr), -length / 2);
+	glVertex3f (0.0, 0.0, -length / 2);
+    }
+    glEnd ();
+}
+
+
+
+static void 
+gear (GLint j, char type[], GLfloat radius, GLfloat width, 
+      GLint teeth, GLfloat tooth_depth) 
+{
+    GLint i;
+    GLfloat r1, r2;
+    GLfloat angle, da;
+    GLfloat u, v, len, fraction = 0.5;
+    GLfloat n = 1.0;
+    GLint indexes[3] =
+    {
+       0, 0, 0
+    };
+    
+    r1 = radius - tooth_depth;
+    r2 = radius;
+    
+    da = 2.0 * M_PI / teeth / 4.0;
+    if (!g[j].face)
+    {
+	fraction = -0.5;
+	n = -1.0;
+    }
+    if (!(strcmp (type, "NORMAL")))
+    {
+	fraction = 0.5;
+	n = 1.0;
+    }
+
+    /* draw front face */ 
+    if (!(strcmp (type, "NORMAL")))
+    {
+	glNormal3f (0.0, 0.0, 1.0 * n);
+	glBegin (GL_QUAD_STRIP);
+	for (i = 0; i <= teeth; i++)
+	{
+	    angle = i * 2.0 * M_PI / teeth;
+	    glVertex3f (0.0, 0.0, width * fraction);
+	    glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
+	    glVertex3f (0.0, 0.0, width * fraction);
+	    glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
+	}
+	glEnd ();
+    }
+    else
+    {
+	glNormal3f (0.0, 0.0, 1.0 * n);
+	glBegin (GL_QUAD_STRIP);
+	for (i = 0; i <= teeth; i++)
+	{
+	    angle = i * 2.0 * M_PI / teeth;
+	    glVertex3f (0.0, 0.0, width * fraction);
+	    glVertex3f ((r2 - width) * cos (angle), (r2 - width) * sin (angle), width * fraction);
+	    glVertex3f (0.0, 0.0, width * fraction);
+	    glVertex3f ((r2 - width) * cos (angle + 3 * da), (r2 - width) * sin (angle + 3 * da), width * fraction);
+	}
+	glEnd ();
+    }
+  
+    /* draw front sides of teeth */ 
+    if (!(strcmp (type, "NORMAL")))
+    {
+	glNormal3f (0.0, 0.0, 1.0 * n);
+	glBegin (GL_QUADS);
+	da = 2.0 * M_PI / teeth / 4.0;
+	for (i = 0; i < teeth; i++)
+	{
+	    angle = i * 2.0 * M_PI / teeth;
+	    glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
+	    glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), width * fraction);
+	    glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), width * fraction);
+	    glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
+	}
+	glEnd ();
+    }
+  
+    glNormal3f (0.0, 0.0, -1.0 * n);
+  
+    /* draw back face */ 
+    glBegin (GL_QUAD_STRIP);
+    for (i = 0; i <= teeth; i++)
+    {
+	angle = i * 2.0 * M_PI / teeth;
+	glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
+	glVertex3f (0.0, 0.0, -width * fraction);
+	glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
+	glVertex3f (0.0, 0.0, -width * fraction);
+    }
+    glEnd ();
+  
+    /* draw back sides of teeth */ 
+    glNormal3f (0.0, 0.0, -1.0 * n);
+    glBegin (GL_QUADS);
+    da = 2.0 * M_PI / teeth / 4.0;
+    for (i = 0; i < teeth; i++)
+    {
+	angle = i * 2.0 * M_PI / teeth;
+	glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
+	glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), -width * fraction);
+	glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), -width * fraction);
+	glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
+    }
+    glEnd ();
+    
+    
+    /* draw outward faces of teeth */ 
+    if (!(strcmp (type, "NORMAL")))
+    {
+	glBegin (GL_QUAD_STRIP);
+	for (i = 0; i < teeth; i++)
+	{
+	    angle = i * 2.0 * M_PI / teeth;
+	    
+	    glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
+	    glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
+	    u = r2 * cos (angle + da) - r1 * cos (angle);
+	    v = r2 * sin (angle + da) - r1 * sin (angle);
+	    len = sqrt (u * u + v * v);
+	    u /= len;
+	    v /= len;
+	    glNormal3f (v, -u, 0.0);
+	    glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), width * fraction);
+	    glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), -width * fraction);
+	    glNormal3f (cos (angle), sin (angle), 0.0);
+	    glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), width * fraction);
+	    glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), -width * fraction);
+	    u = r1 * cos (angle + 3 * da) - r2 * cos (angle + 2 * da);
+	    v = r1 * sin (angle + 3 * da) - r2 * sin (angle + 2 * da);
+	    glNormal3f (v, -u, 0.0);
+	    glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
+	    glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
+	    glNormal3f (cos (angle), sin (angle), 0.0);
+	}
+    }
+    else
+    {
+	glBegin (GL_QUAD_STRIP);
+	for (i = 0; i < teeth; i++)
+	{
+	    angle = i * 2.0 * M_PI / teeth;
+	    glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
+	    glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
+	    u = r2 * cos (angle + da) - r1 * cos (angle);
+	    v = r2 * sin (angle + da) - r1 * sin (angle);
+	    len = sqrt (u * u + v * v);
+	    u /= len;
+	    v /= len;
+	    glNormal3f (v, -u, 0.0);
+	    glVertex3f ((r2 - width) * cos (angle + da), (r2 - width) * sin (angle + da), width * fraction);
+	    glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), -width * fraction);
+	    glNormal3f (cos (angle), sin (angle), n);
+	    glVertex3f ((r2 - width) * cos (angle + 2 * da), (r2 - width) * sin (angle + 2 * da), width * fraction);
+	    glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), -width * fraction);
+	    u = r1 * cos (angle + 3 * da) - r2 * cos (angle + 2 * da);
+	    v = r1 * sin (angle + 3 * da) - r2 * sin (angle + 2 * da);
+	    glNormal3f (v, -u, 0.0);
+	    glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
+	    glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
+	    glNormal3f (cos (angle), sin (angle), n);
+	}
+    }
+    
+    glVertex3f (r1 * cos (0), r1 * sin (0), width * fraction);
+    glVertex3f (r1 * cos (0), r1 * sin (0), -width * fraction);
+    glEnd ();
+}
+
+
+static void 
+belt (struct GEAR g1, struct GEAR g2) 
+{
+    GLfloat D, alpha, phi, angle, incr, width;
+    GLint indexes[3] =
+    {
+       0, 0, 0
+    };
+    
+    GLfloat col[3] =
+    {
+       0.0, 0.0, 0.0
+    };
+    
+    width = min (g1.width, g2.width);
+    D = sqrt (pow (g1.position[0] - g2.position[0], 2) + pow (g1.position[1] - g2.position[1], 2) + pow (g1.position[2] - g2.position[2], 2));
+    alpha = acos ((g2.position[0] - g1.position[0]) / D);
+    phi = acos ((g1.radius - g2.radius) / D);
+    glBegin (GL_QUADS);
+    glColor3fv (col);
+    glMaterialiv (GL_FRONT, GL_COLOR_INDEXES, indexes);
+    incr = 1.2 * 360.0 / g1.teeth * M_PI / 180.00;
+    for (angle = alpha + phi; angle <= 2 * M_PI - phi + alpha; angle += 360.0 / g1.teeth * M_PI / 180.00)
+    {
+	glNormal3f (cos (angle), sin (angle), 0.0);
+	glVertex3f (g1.radius * cos (angle), g1.radius * sin (angle), width * 0.5);
+	glVertex3f (g1.radius * cos (angle), g1.radius * sin (angle), -width * 0.5);
+	glVertex3f (g1.radius * cos (angle + incr), g1.radius * sin (angle + incr), -width * 0.5);
+	glVertex3f (g1.radius * cos (angle + incr), g1.radius * sin (angle + incr), width * 0.5);
+    }
+    glEnd ();
+    glBegin (GL_QUADS);
+    glColor3fv (col);
+    glMaterialiv (GL_FRONT, GL_COLOR_INDEXES, indexes);
+    incr = 1.2 * 360.0 / g2.teeth * M_PI / 180.00;
+    for (angle = -phi + alpha; angle <= phi + alpha; angle += 360.0 / g1.teeth * M_PI / 180.0)
+    {
+	glNormal3f (cos (angle), sin (angle), 0.0);
+	glVertex3f (g2.radius * cos (angle) + g2.position[0] - g1.position[0], g2.radius * sin (angle) + g2.position[1] - g1.position[1], width * 0.5);
+	glVertex3f (g2.radius * cos (angle) + g2.position[0] - g1.position[0], g2.radius * sin (angle) + g2.position[1] - g1.position[1], width * -0.5);
+	glVertex3f (g2.radius * cos (angle + incr) + g2.position[0] - g1.position[0], g2.radius * sin (angle + incr) + g2.position[1] - g1.position[1], width * -0.5);
+	glVertex3f (g2.radius * cos (angle + incr) + g2.position[0] - g1.position[0], g2.radius * sin (angle + incr) + g2.position[1] - g1.position[1], width * 0.5);
+    }
+    glEnd ();
+
+    glBegin (GL_QUADS);
+    glColor3fv (col);
+    glMaterialiv (GL_FRONT, GL_COLOR_INDEXES, indexes);
+    glVertex3f (g1.radius * cos (alpha + phi), g1.radius * sin (alpha + phi), width * 0.5);
+    glVertex3f (g1.radius * cos (alpha + phi), g1.radius * sin (alpha + phi), width * -0.5);
+    glVertex3f (g2.radius * cos (alpha + phi) + g2.position[0] - g1.position[0], g2.radius * sin (alpha + phi) + g2.position[1] - g1.position[1], width * -0.5);
+    glVertex3f (g2.radius * cos (alpha + phi) + g2.position[0] - g1.position[0], g2.radius * sin (alpha + phi) + g2.position[1] - g1.position[1], width * 0.5);
+    glVertex3f (g1.radius * cos (alpha - phi), g1.radius * sin (alpha - phi), width * 0.5);
+    glVertex3f (g1.radius * cos (alpha - phi), g1.radius * sin (alpha - phi), width * -0.5);
+    glVertex3f (g2.radius * cos (alpha - phi) + g2.position[0] - g1.position[0], g2.radius * sin (alpha - phi) + g2.position[1] - g1.position[1], width * -0.5);
+    glVertex3f (g2.radius * cos (alpha - phi) + g2.position[0] - g1.position[0], g2.radius * sin (alpha - phi) + g2.position[1] - g1.position[1], width * 0.5);
+    glEnd ();
+}
+
+
+int 
+axle_find (char axle_name[]) 
+{
+    int i;
+    
+    for (i = 0; i < number_of_axles; i++)
+    {
+	if (!(strcmp (axle_name, a[i].name)))
+           break;
+    }
+    return i;
+}
+
+
+int 
+gear_find (char gear_name[]) 
+{
+    int i;
+    
+    for (i = 0; i < number_of_gears; i++)
+    {
+	if (!(strcmp (gear_name, g[i].name)))
+           break;
+    }
+    return i;
+}
+
+
+void 
+process () 
+{
+    GLfloat x, y, z, D, dist;
+    GLint axle_index, i, j, g1, g2, k;
+    char error[80];
+    
+    for (i = 0; i < number_of_gears; i++)
+    {
+	x = 0.0;
+	y = 0.0;
+	z = 0.0;
+	axle_index = axle_find (g[i].axle_name);
+	g[i].axis = a[axle_index].axis;
+	g[i].motored = a[axle_index].motored;
+	if (a[axle_index].motored)
+	{
+	    g[i].direction = a[axle_index].direction;
+	    g[i].angular_velocity = a[axle_index].angular_velocity;
+	}
+	if (g[i].axis == 0)
+           x = 1.0;
+        else if (g[i].axis == 1)
+           y = 1.0;
+        else
+           z = 1.0;
+      
+	g[i].position[0] = a[axle_index].position[0] + x * g[i].relative_position;
+	g[i].position[1] = a[axle_index].position[1] + y * g[i].relative_position;
+	g[i].position[2] = a[axle_index].position[2] + z * g[i].relative_position;
+    }
+  
+    for (k = 0; k < number_of_axles; k++)
+    {
+	for (i = 0; i < number_of_gears - 1; i++)
+	{
+	    for (j = 0; j < number_of_gears; j++)
+	    {
+		if (!(strcmp (g[i].type, g[j].type)) && (!(strcmp (g[i].type, "NORMAL"))) && ((strcmp (g[i].axle_name, g[j].axle_name) != 0)) && (g[i].axis == g[j].axis))
+		{
+		    D = sqrt (pow (g[i].position[0] - g[j].position[0], 2) + pow (g[i].position[1] - g[j].position[1], 2) + pow (g[i].position[2] - g[j].position[2], 2));
+		    if (D < 1.1 * (g[i].radius - g[i].tooth_depth + g[j].radius - g[j].tooth_depth))
+		    {
+			printf (error, "Gear %s and %s are too close to each other.", g[i].name, g[j].name);
+		      
+                        /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+			exit (1);
+		    }
+		  
+		    if (g[i].axis == 0)
+		    {
+			dist = g[i].position[0] - g[j].position[0];
+		    }
+		    else if (g[i].axis == 1)
+		    {
+			dist = g[i].position[1] - g[j].position[1];
+		    }
+		    else
+                       dist = g[i].position[2] - g[j].position[2];
+		  
+		    dist = fabs (dist);
+		    
+		    if (dist < (g[i].width / 2 + g[j].width / 2))
+		    {
+			if ((g[i].motored) && (!(g[j].motored)) && (D < 0.95 * (g[i].radius + g[j].radius)))
+			{
+			    axle_index = axle_find (g[j].axle_name);
+			    if ((a[axle_index].direction != 0) && (g[j].angular_velocity != g[i].angular_velocity * g[i].teeth / g[j].teeth * g[i].radius / g[j].radius))
+			    {
+				printf (error, "Error in tooth linkage of gears %s and %s.", g[i].name, g[j].name);
+                                /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+				exit (1);
+			    }
+			  
+			    g[j].motored = (a[axle_index].motored = 1);
+			    g[j].direction = (a[axle_index].direction = -g[i].direction);
+			    a[axle_index].angular_velocity = g[i].angular_velocity * g[i].teeth / g[j].teeth;
+			    g[j].angular_velocity = (a[axle_index].angular_velocity *= g[i].radius / g[j].radius);
+			}
+		      
+			if ((!(g[i].motored)) && (g[j].motored) && (D < 0.95 * (g[i].radius + g[j].radius)))
+			{
+			    axle_index = axle_find (g[i].axle_name);
+			    if ((a[axle_index].direction != 0) && (g[i].angular_velocity != g[j].angular_velocity * g[j].teeth / g[i].teeth * g[j].radius / g[i].radius))
+			    {
+				printf (error, "Error in tooth linkage of gears %s and %s.", g[i].name, g[j].name);
+                                /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+				exit (1);
+			    }
+			  
+			    g[i].motored = (a[axle_index].motored = 1);
+			    g[i].direction = (a[axle_index].direction = -g[j].direction);
+			    a[axle_index].angular_velocity = g[j].angular_velocity * g[j].teeth / g[i].teeth;
+			    g[i].angular_velocity = (a[axle_index].angular_velocity *= g[j].radius / g[i].radius);
+			  
+			}
+		    }
+		}
+	      
+		if (!(strcmp (g[i].type, g[j].type)) && (!(strcmp (g[i].type, "BEVEL"))) && ((strcmp (g[i].axle_name, g[j].axle_name) != 0)) && (g[i].axis != g[j].axis))
+		{
+		    D = sqrt (pow (g[i].position[0] - g[j].position[0], 2) + pow (g[i].position[1] - g[j].position[1], 2) + pow (g[i].position[2] - g[j].position[2], 2));
+		    if ((g[i].motored) && (!(g[j].motored)) && (D < 0.95 * sqrt (g[i].radius * g[i].radius + g[j].radius * g[j].radius)))
+		    {
+			axle_index = axle_find (g[j].axle_name);
+			if ((a[axle_index].direction != 0) && (g[j].angular_velocity != g[i].angular_velocity * g[i].teeth / g[j].teeth * g[i].radius / g[j].radius))
+			{
+			    printf (error, "Error in tooth linkage of gears %s and %s.", g[i].name, g[j].name);
+                            /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+			    exit (1);
+			}
+			g[j].motored = (a[axle_index].motored = 1);
+			g[j].direction = (a[axle_index].direction = -g[i].direction);
+			a[axle_index].angular_velocity = g[i].angular_velocity * g[i].teeth / g[j].teeth;
+			g[j].angular_velocity = (a[axle_index].angular_velocity *= g[i].radius / g[j].radius);
+		    }
+		  
+		    
+		    if ((!(g[i].motored)) && (g[j].motored) && (D < 0.95 * sqrt (g[i].radius * g[i].radius + g[j].radius * g[j].radius)))
+		    {
+			axle_index = axle_find (g[i].axle_name);
+			if ((a[axle_index].direction != 0) && (g[i].angular_velocity != g[j].angular_velocity * g[j].teeth / g[i].teeth * g[j].radius / g[i].radius))
+			{
+			    printf (error, "Error in tooth linkage of gears %s and %s.", g[i].name, g[j].name);
+                            /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+			    exit (1);
+			}
+			g[i].motored = (a[axle_index].motored = 1);
+			g[i].direction = (a[axle_index].direction = -g[j].direction);
+			a[axle_index].angular_velocity = g[j].angular_velocity * g[j].teeth / g[i].teeth;
+			g[i].angular_velocity = (a[axle_index].angular_velocity *= g[j].radius / g[i].radius);
+		    }
+		}
+	    }
+	}
+      
+	for (i = 0; i < number_of_gears; i++)
+	{
+	    axle_index = axle_find (g[i].axle_name);
+	    g[i].motored = a[axle_index].motored;
+	    if (a[axle_index].motored)
+	    {
+		g[i].direction = a[axle_index].direction;
+		g[i].angular_velocity = a[axle_index].angular_velocity;
+	    }
+	}
+      
+	for (i = 0; i < number_of_belts; i++)
+	{
+	    g1 = gear_find (b[i].gear1_name);
+	    g2 = gear_find (b[i].gear2_name);
+	    D = sqrt (pow (g[g1].position[0] - g[g2].position[0], 2) + pow (g[g1].position[1] - g[g2].position[1], 2) + pow (g[g1].position[2] - g[g2].position[2], 2));
+	    if (!((g[g1].axis == g[g2].axis) && (!strcmp (g[g1].type, g[g2].type)) && (!strcmp (g[g1].type, "NORMAL"))))
+	    {
+		printf (error, "Belt %s invalid.", b[i].name);
+                /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+		exit (1);
+	    }
+	  
+	    if ((g[g1].axis == g[g2].axis) && (!strcmp (g[g1].type, g[g2].type)) && (!strcmp (g[g1].type, "NORMAL")))
+	    {
+	      /*
+	         if((g[g1].motored)&&(g[g2].motored))
+	         if(g[g2].angular_velocity!=(g[g1].angular_velocity*g[g1].radius/g[g2].radius))
+	         {
+	         printf(error,"Error in belt linkage of gears %s and %s".,g[g1].name,g[g2].name);
+	         MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);
+	         exit(1);
+	         }
+              */ 
+               if (g[g1].axis == 0)
+                  {
+		    dist = g[g1].position[0] - g[g2].position[0];
+		}
+		else if (g[i].axis == 1)
+		{
+		    dist = g[g1].position[1] - g[g2].position[1];
+		}
+		else
+                   dist = g[g1].position[2] - g[g2].position[2];
+	      
+		dist = fabs (dist);
+		
+		if (dist > (g[g1].width / 2 + g[g2].width / 2))
+		{
+		    printf (error, "Belt %s invalid.", b[i].name);
+                    /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+		    exit (1);
+		}
+	      
+		if (dist < (g[g1].width / 2 + g[g2].width / 2))
+		{
+		    if (D < g[g1].radius + g[g2].radius)
+		    {
+			printf (error, "Gears %s and %s too close to be linked with belts", g[g1].name, g[g2].name);
+                        /*MessageBox(NULL,error,windowName,MB_ICONEXCLAMATION|MB_OK);*/
+			exit (1);
+		    }
+		  
+		    if ((g[g1].motored) && (!(g[g2].motored)))
+		    {
+			axle_index = axle_find (g[g2].axle_name);
+			g[g2].motored = (a[axle_index].motored = 1);
+			g[g2].direction = (a[axle_index].direction = g[g1].direction);
+			g[g2].angular_velocity = (a[axle_index].angular_velocity = g[g1].angular_velocity * g[g1].radius / g[g2].radius);
+		    }
+		  
+		    if ((!(g[g1].motored)) && (g[g2].motored))
+		    {
+			axle_index = axle_find (g[g1].axle_name);
+			g[g1].motored = (a[axle_index].motored = 1);
+			g[g1].direction = (a[axle_index].direction = g[g2].direction);
+			g[g1].angular_velocity = (a[axle_index].angular_velocity = g[g2].angular_velocity * g[g2].radius / g[g1].radius);
+		    }
+		}
+	    }
+	}
+      
+	for (i = 0; i < number_of_gears; i++)
+	{
+	    axle_index = axle_find (g[i].axle_name);
+	    g[i].motored = a[axle_index].motored;
+	    if (a[axle_index].motored)
+	    {
+		g[i].direction = a[axle_index].direction;
+		g[i].angular_velocity = a[axle_index].angular_velocity;
+	    }
+	}
+    }
+}
+
+
+
+GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 10.0;
+
+
+static void 
+draw (void) 
+{
+    int i;
+    GLfloat x, y, z;
+    int index;
+
+    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    
+    glPushMatrix ();
+    glRotatef (view_rotx, 1.0, 0.0, 0.0);
+    glRotatef (view_roty, 0.0, 1.0, 0.0);
+    glRotatef (view_rotz, 0.0, 0.0, 1.0);
+    
+    for (i = 0; i < number_of_gears; i++)
+    {
+	x = 0.0;
+	y = 0.0;
+	z = 0.0;
+	glPushMatrix ();
+/*glTranslatef( -3.0, -2.0, 0.0 );*/
+	glTranslatef (g[i].position[0], g[i].position[1], g[i].position[2]);
+	if (g[i].axis == 0)
+           y = 1.0;
+        else if (g[i].axis == 1)
+           x = 1.0;
+        else
+           z = 1.0;
+      
+	if (z != 1.0)
+           glRotatef (90.0, x, y, z);
+      
+	glRotatef (g[i].direction * g[i].angle, 0.0, 0.0, 1.0);
+	glCallList (g[i].id);
+	glPopMatrix ();
+    }
+  
+    for (i = 0; i < number_of_axles; i++)
+    {
+	x = 0.0;
+	y = 0.0;
+	z = 0.0;
+	glPushMatrix ();
+	glTranslatef (a[i].position[0], a[i].position[1], a[i].position[2]);
+	if (a[i].axis == 0)
+           y = 1.0;
+        else if (a[i].axis == 1)
+           x = 1.0;
+        else
+           z = 1.0;
+
+	if (z != 1.0)
+           glRotatef (90.0, x, y, z);
+      
+	glCallList (a[i].id);
+	glPopMatrix ();
+    }
+  
+    for (i = 0; i < number_of_belts; i++)
+    {
+	x = 0.0;
+	y = 0.0;
+	z = 0.0;
+	glPushMatrix ();
+	index = gear_find (b[i].gear1_name);
+	glTranslatef (g[index].position[0], g[index].position[1], g[index].position[2]);
+	if (g[index].axis == 0)
+           y = 1.0;
+        else if (g[index].axis == 1)
+           x = 1.0;
+        else
+           z = 1.0;
+      
+	if (z != 1.0)
+           glRotatef (90.0, x, y, z);
+      
+	glCallList (b[i].id);
+	glPopMatrix ();
+    }
+  
+    glPopMatrix ();
+    glutSwapBuffers ();
+}
+
+
+
+
+static void 
+idle (void) 
+{
+    int i;
+    for (i = 0; i < number_of_gears; i++)
+      g[i].angle += g[i].angular_velocity;
+    glutPostRedisplay();
+}
+
+
+
+
+/* change view angle, exit upon ESC */ 
+static void 
+key (unsigned char k, int x, int y) 
+{
+    switch (k)
+    {
+    case 'x':
+	view_rotx += 5.0;
+        break;
+    case 'X':
+	view_rotx -= 5.0;
+        break;
+    case 'y':
+	view_roty += 5.0;
+        break;
+    case 'Y':
+	view_roty -= 5.0;
+        break;
+    case 'z':
+	view_rotz += 5.0;
+        break;
+    case 'Z':
+	view_rotz -= 5.0;
+        break;
+    case 0x1B:
+	exit(0);
+    }
+}
+
+
+
+
+/* new window size or exposure */ 
+static void 
+reshape (int width, int height) 
+{
+    glViewport (0, 0, (GLint) width, (GLint) height);
+    glMatrixMode (GL_PROJECTION);
+    glLoadIdentity ();
+    if (width > height)
+    {
+	GLfloat w = (GLfloat) width / (GLfloat) height;
+	glFrustum (-w, w, -1.0, 1.0, 5.0, 60.0);
+    }
+    else
+    {
+	GLfloat h = (GLfloat) height / (GLfloat) width;
+	glFrustum (-1.0, 1.0, -h, h, 5.0, 60.0);
+    }
+    
+    glMatrixMode (GL_MODELVIEW);
+    glLoadIdentity ();
+    glTranslatef (0.0, 0.0, -40.0);
+    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+}
+
+
+
+static void 
+init (void) 
+{
+    GLfloat matShine = 20.00F;
+    GLfloat light0Pos[4] =
+    {
+       0.70F, 0.70F, 1.25F, 0.50F
+    };
+    int i;
+    
+    glClearColor (background[0], background[1], background[2], 1.0F);
+    glClearIndex ((GLfloat) 0.0);
+    
+    glMaterialf (GL_FRONT_AND_BACK, GL_SHININESS, matShine);
+    glLightfv (GL_LIGHT0, GL_POSITION, light0Pos);
+    glEnable (GL_LIGHT0);
+  
+    glEnable (GL_LIGHTING);
+    glEnable (GL_DEPTH_TEST);
+    for (i = 0; i < number_of_gears; i++)
+      g[i].angle = 0.0;
+  
+    for (i = 0; i < number_of_gears; i++)
+    {
+	g[i].id = glGenLists (1);
+	glNewList (g[i].id, GL_COMPILE);
+	glColor3fv (g[i].color);
+	glMaterialfv (GL_FRONT, GL_SPECULAR, g[i].color);
+	gear (i, g[i].type, g[i].radius, g[i].width, g[i].teeth, g[i].tooth_depth);
+	glEndList ();
+    }
+  
+    for (i = 0; i < number_of_axles; i++)
+    {
+	a[i].id = glGenLists (1);
+	glNewList (a[i].id, GL_COMPILE);
+	glColor3fv (a[i].color);
+	glMaterialfv (GL_FRONT, GL_SPECULAR, a[i].color);
+	axle (i, a[i].radius, a[i].length);
+	glEndList ();
+    }
+  
+    for (i = 0; i < number_of_belts; i++)
+    {
+	b[i].id = glGenLists (1);
+	glNewList (b[i].id, GL_COMPILE);
+	belt (g[gear_find (b[i].gear1_name)], g[gear_find (b[i].gear2_name)]);
+	glEndList ();
+    }
+  
+    glEnable (GL_COLOR_MATERIAL);
+}
+
+
+
+int 
+main (int argc, char *argv[]) 
+{
+    char *file;
+
+    if (argc < 2)
+       file = "geartrain.dat";
+    else
+       file = argv[1];
+
+    glutInitWindowPosition (0, 0);
+    glutInitWindowSize(640,480);
+    glutInitDisplayMode (GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
+    
+    if (glutCreateWindow ("Gear Train Simulation") == GL_FALSE)
+      exit (1);
+
+    getdata (file);
+    process ();
+    init ();
+    
+    glutDisplayFunc (draw);
+    glutReshapeFunc (reshape);
+    glutKeyboardFunc (key);
+    glutIdleFunc (idle);
+    glutMainLoop ();
+    return 0;
+}
+
diff --git a/progs/demos/geartrain.dat b/progs/demos/geartrain.dat
new file mode 100644
index 0000000..6b46745
--- /dev/null
+++ b/progs/demos/geartrain.dat
@@ -0,0 +1,119 @@
+BACKGROUND = 0.000 0.500 0.700
+
+ANAME = AXLE1
+ARADIUS = 1.000
+AAXIS = 2
+APOSITION = -7.000 0.000 0.000
+ACOLOR = 0.800 0.500 0.200
+ALENGTH = 6.000
+AMOTORED = 1
+AANGULARVELOCITY = 2.000
+ADIRECTION = 1
+
+ANAME = AXLE2
+ARADIUS = 1.000
+AAXIS = 2
+APOSITION = -3.000 0.000 0.000
+ACOLOR = 0.800 0.500 0.200
+ALENGTH = 12.000
+AMOTORED = 0
+
+ANAME = AXLE3
+ARADIUS = 1.000
+AAXIS = 2
+APOSITION = 1.000 0.000 0.000
+ACOLOR = 0.800 0.500 0.200
+ALENGTH = 6.000
+AMOTORED = 0
+
+ANAME = AXLE4
+ARADIUS = 1.000
+AAXIS = 2
+APOSITION = 8.000 0.000 0.000
+ACOLOR = 0.800 0.500 0.200
+ALENGTH = 18.000
+AMOTORED = 0
+
+ANAME = AXLE5
+ARADIUS = 1.000
+AAXIS = 1
+APOSITION = 8.000 -8.200 -7.400
+ACOLOR = 0.800 0.500 0.200
+ALENGTH = 12.000
+AMOTORED = 0
+
+GNAME = GEAR1
+GTYPE = NORMAL
+GRADIUS = 2.200
+GWIDTH = 3.000
+GTEETH = 40
+GTOOTHDEPTH = 0.500
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE1
+GPOSITION = 0.000
+
+GNAME = GEAR2
+GTYPE = NORMAL
+GRADIUS = 2.200
+GWIDTH = 3.000
+GTEETH = 30
+GTOOTHDEPTH = 0.500
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE2
+GPOSITION = 0.000
+
+GNAME = GEAR3
+GTYPE = NORMAL
+GRADIUS = 2.200
+GWIDTH = 3.000
+GTEETH = 20
+GTOOTHDEPTH = 0.500
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE3
+GPOSITION = 0.000
+
+GNAME = GEAR4
+GTYPE = NORMAL
+GRADIUS = 1.700
+GWIDTH = 1.000
+GTEETH = 20
+GTOOTHDEPTH = 0.500
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE2
+GPOSITION = 5.000
+
+GNAME = GEAR5
+GTYPE = NORMAL
+GRADIUS = 3.000
+GWIDTH = 1.000
+GTEETH = 20
+GTOOTHDEPTH = 0.500
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE4
+GPOSITION = 5.000
+
+GNAME = GEAR6
+GTYPE = BEVEL
+GFACE = 0
+GRADIUS = 4.000
+GWIDTH = 1.000
+GTEETH = 20
+GTOOTHDEPTH = 1.700
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE4
+GPOSITION = -4.000
+
+GNAME = GEAR7
+GTYPE = BEVEL
+GFACE = 0
+GRADIUS = 4.000
+GWIDTH = 1.000
+GTEETH = 20
+GTOOTHDEPTH = 1.700
+GCOLOR = 0.500 0.500 0.500
+GAXLE = AXLE5
+GPOSITION = 5.000
+
+BELTNAME = BELT1
+GEAR1NAME = GEAR5
+GEAR2NAME = GEAR4