T1 = Z1^2 T2 = X1-T1 T1 = X1+T1 T2 = T2*T1 T2 = 3*T2 Y3 = 2*Y1 Z3 = Y3*Z1 Y3 = Y3^2 T3 = Y3*X1 Y3 = Y3^2 Y3 = half*Y3 X3 = T2^2 T1 = 2*T3 X3 = X3-T1 T1 = T3-X3 T1 = T1*T2 Y3 = T1-Y3