# Desargues Theorem
Let(O=[0,0], A=[u1,0], A1=[u2,0], B=[0,u3], C=[u4,u5], B1=[0,x1], C1=[x2,x3]):
Desargues := Theorem(
     [arbitrary(A,B,C), parallel(A,B,A1,B1), parallel(B,C,B1,C1),
      parallel(C,A,C1,A1), online(O,A,A1), online(O,B,B1)],
     online(O,C,C1), [x1,x2,x3]);
