Ví dụ 1: animation point

A = (-2.92, 4.9)
B = (3.72, 4.94)
a = Segment(A, B)
b = 3.2 (slider from 0 to 10, step 0.1)
d = Distance(A, B)
c = Circle(A, d * b / 10.0)
C, D = Intersect(c, a)