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u1 v1 u2 v2 u3 v3 x1 x2 x3 y4 y5 y6
# Pappus theorem
# A(x1,0), B(x2,0) and C(x3,0) are on one line.
# D(0,y4), E(0,y5) and F(0,y6) are on the other line.

x1 v1 + u1 y5 - x1 y5

x2 v1 + u1 y4 - x2 y4

x1 v2 + u2 y6 - x1 y6

x3 v2 + u2 y4 - x3 y4

x2 v3 + u3 y6 - x2 y6

x3 v3 + u3 y5 - x3 y5









