A = Intersect(xAxis, yAxis)
B = Point(xAxis)
C: B + 0.5 * Vector[A, B]
c = Semicircle(A, B)
d = Semicircle(C, B)
D: C + 0.5 * Vector[B, C]
e = Semicircle(C, D)
f, g, E, F = halbkreis(C, D)
h, k, G, H = halbkreis(E, F)
Text1: "Kreisumfang u = " + (Length[Vector[A, B]] * 3.141592653589793)
Text2: "Näherung: l = " + (c + d + e + f + g + h + k)

Tool: halbkreis
Input: A, B
Output: d, e, C, D

C: B + 0.5 * Vector[A, B]
d = Semicircle(C, B)
D: C + 0.5 * Vector[B, C]
e = Semicircle(C, D)