a = (-1, 1)
b = (0, 1)
T1: " M = (a \; b) = 
\left( \begin{array}{cc}" + (x(a)) + " & " + (x(b)) + "\\" + (y(a)) + " & " + (y(b)) + "
\end{array} \right)"
A = Corner(pic1, 1.0)
A': (x(a) * x(A) + x(b) * y(A), y(a) * x(A) + y(b) * y(A))
B = Corner(pic1, 2.0)
C = Corner(pic1, 4.0)
P, d, a_1, c = Polygon(A, B, C)
B': (x(a) * x(B) + x(b) * y(B), y(a) * x(B) + y(b) * y(B))
C': (x(a) * x(C) + x(b) * y(C), y(a) * x(C) + y(b) * y(C))
Q, c', a', b' = Polygon(A', B', C')