source 2005 Dimitrov--Imbert--Mishra compute M = 3 X1^2+a Z1^4 compute E = 12 X1 Y1^2-M^2 compute T = 8 Y1^4 compute X3 = 8 Y1^2 (T-M E)+X1 E^2 compute Y3 = Y1 (4 (M E-T) (2 T-M E)-E^3) compute Z3 = Z1 E