t0 = Y1-X1 t1 = Y2-X2 A = t0*t1 t2 = Y1+X1 t3 = Y2+X2 B = t2*t3 t4 = k*T2 C = T1*t4 E = B-A F = 2-C G = 2+C H = B+A X3 = E*F Y3 = G*H T3 = E*H t5 = C^2 Z3 = 4-t5