name extended coordinates
variable X
variable Y
variable Z
variable T
neutral X = 0
neutral Y = 1
neutral Z = 1
neutral T = 0
satisfying x = X/Z
satisfying y = Y/Z
satisfying x*y = T/Z
toaffine x = X/Z
toaffine y = Y/Z
tosystem X = x
tosystem Y = y
tosystem Z = 1
tosystem T = x*y
homogweight X = 1
homogweight Y = 1
homogweight Z = 1
homogweight T = 3
