Elementen Boek I Propositie 01

lengte = 4 (slider from 0 to 5, step 0.1)
B = (-3, 0)
A = Intersect(xAxis, yAxis)
c = Circle(A, lengte)
C = Intersect(c, xAxis, 2)
d = Circle(C, A)
D = Intersect(c, d, 1)
veelhoek1, d_1, a, c_1 = Polygon(A, C, D)
stap = 5 (slider from 0 to 5, step 1)