Crossed parallelogram
Author: Chris Sangwin
Date: 27 December 2006

In the following crossed parallelogram, move B to a fixed position.  Then, what is the path of the intersection of the crossed bars as the point C is moved?

A = Intersect(xAxis, yAxis)
a = 4
c = Circle(A, a)
b = 8
d = Circle(A, b)
B = Point(c)
e = 8
f = Circle(B, e)
C = Point(f)
g = 4
h = Circle(C, g)
i = Segment(A, B)
j = Segment(B, C)
D = Intersect(d, h, 1)
k = Segment(A, D)
l = Segment(D, C)
P = Intersect(j, k)