# Steiner Theorem (Yang & Zhang, 1992)
Let(A=[0,0], B=[1,0], C=[u1,u2], C1=[x1,x2], B1=[x3,x4], A1=[x5,x6]):
Steiner := Theorem(
    [arbitrary(A,B,C), equidistance(A,C1,B,C1), equidistance(A,C1,A,B),       
     equidistance(A,B1,A,C), equidistance(A,B1,C,B1),
     equidistance(B,A1,B,C), equidistance(B,A1,C,A1)],
    concurrent(A,A1,B,B1,C,C1), [x1,x2,x3,x4,x5,x6]);
