diff --git a/builtin_function.cpp b/builtin_function.cpp
index bc04090..c75805c 100644
--- a/builtin_function.cpp
+++ b/builtin_function.cpp
@@ -131,12 +131,12 @@
    "     	           (constant float (0.0742610))\n"
    "	           (expression float abs (var_ref x))))))))))\n"
    "\n"
-   "   (signature float\n"
+   "   (signature vec2\n"
    "     (parameters\n"
    "       (declare (in) vec2 x))\n"
    "     ((return (expression vec2 *\n"
-   "     	       (expression vec2 -\n"
-   "	        (expression vec2 *\n"
+   "     	       (expression float -\n"
+   "	        (expression float *\n"
    "		 (constant float (3.1415926))\n"
    "		 (constant float (0.5)))\n"
    "		(expression vec2 sqrt\n"
@@ -153,12 +153,12 @@
    "     	           (constant float (0.0742610))\n"
    "	           (expression vec2 abs (var_ref x))))))))))\n"
    "\n"
-   "   (signature float\n"
+   "   (signature vec3\n"
    "     (parameters\n"
    "       (declare (in) vec3 x))\n"
    "     ((return (expression vec3 *\n"
    "     	       (expression vec3 -\n"
-   "	        (expression vec3 *\n"
+   "	        (expression float *\n"
    "		 (constant float (3.1415926))\n"
    "		 (constant float (0.5)))\n"
    "		(expression vec3 sqrt\n"
@@ -175,12 +175,12 @@
    "     	           (constant float (0.0742610))\n"
    "	           (expression vec3 abs (var_ref x))))))))))\n"
    "\n"
-   "   (signature float\n"
+   "   (signature vec4\n"
    "     (parameters\n"
    "       (declare (in) vec4 x))\n"
    "     ((return (expression vec4 *\n"
    "     	       (expression vec4 -\n"
-   "	        (expression vec4 *\n"
+   "	        (expression float *\n"
    "		 (constant float (3.1415926))\n"
    "		 (constant float (0.5)))\n"
    "		(expression vec4 sqrt\n"