diff --git a/Lib/lib-stdwin/CSplit.py b/Lib/lib-stdwin/CSplit.py
new file mode 100644
index 0000000..03559c1
--- /dev/null
+++ b/Lib/lib-stdwin/CSplit.py
@@ -0,0 +1,70 @@
+# A CSplit is a Clock-shaped split: the children are grouped in a circle.
+# The numbering is a little different from a real clock: the 12 o'clock
+# position is called 0, not 12.  This is a little easier since Python
+# usually counts from zero.  (BTW, there needn't be exactly 12 children.)
+
+
+from math import pi, sin, cos
+from Split import Split
+
+class CSplit() = Split():
+	#
+	def minsize(self, m):
+		# Since things look best if the children are spaced evenly
+		# along the circle (and often all children have the same
+		# size anyway) we compute the max child size and assume
+		# this is each child's size.
+		width, height = 0, 0
+		for child in self.children:
+			wi, he = child.minsize(m)
+			width = max(width, wi)
+			height = max(height, he)
+		# In approximation, the diameter of the circle we need is
+		# (diameter of box) * (#children) / pi.
+		# We approximate pi by 3 (so we slightly overestimate
+		# our minimal size requirements -- not so bad).
+		# Because the boxes stick out of the circle we add the
+		# box size to each dimension.
+		# Because we really deal with ellipses, do everything
+		# separate in each dimension.
+		n = len(self.children)
+		return width + (width*n + 2)/3, height + (height*n + 2)/3
+	#
+	def getbounds(self):
+		return self.bounds
+	#
+	def setbounds(self, bounds):
+		self.bounds = bounds
+		# Place the children.  This involves some math.
+		# Compute center positions for children as if they were
+		# ellipses with a diameter about 1/N times the
+		# circumference of the big ellipse.
+		# (There is some rounding involved to make it look
+		# reasonable for small and large N alike.)
+		# XXX One day Python will have automatic conversions...
+		n = len(self.children)
+		fn = float(n)
+		if n = 0: return
+		(left, top), (right, bottom) = bounds
+		width, height = right-left, bottom-top
+		child_width, child_height = width*3/(n+4), height*3/(n+4)
+		half_width, half_height = \
+			float(width-child_width)/2.0, \
+			float(height-child_height)/2.0
+		center_h, center_v = center = (left+right)/2, (top+bottom)/2
+		fch, fcv = float(center_h), float(center_v)
+		alpha = 2.0 * pi / fn
+		for i in range(n):
+			child = self.children[i]
+			fi = float(i)
+			fh, fv = \
+				fch + half_width*sin(fi*alpha), \
+				fcv - half_height*cos(fi*alpha)
+			left, top = \
+				int(fh) - child_width/2, \
+				int(fv) - child_height/2
+			right, bottom = \
+				left + child_width, \
+				top + child_height
+			child.setbounds((left, top), (right, bottom))
+	#