name XYZZ coordinates with a4=-3
assume a = -3
variable X
variable Y
variable ZZ
variable ZZZ
neutral X = 1
neutral Y = 1
neutral ZZ = 0
neutral ZZZ = 0
satisfying x = X/ZZ
satisfying y = Y/ZZZ
satisfying ZZ^3 = ZZZ^2
toaffine x = X/ZZ
toaffine y = Y/ZZZ
tosystem X = x
tosystem Y = y
tosystem ZZ = 1
tosystem ZZZ = 1
homogweight X = 2
homogweight Y = 3
homogweight ZZ = 2
homogweight ZZZ = 3
