Pappus's Theorem

Pappus:=proc() local t,s,m,b,m1,b1,i,P,Q:

for i from 1 to 3 do   P[i]:= ParamLine(m,b,t[i]):   Q[i]:=ParamLine(m1,b1,s[i]):   od:

Colinear(
Pt(Le(P[1],Q[2])   ,   Le(P[2],Q[1])),
Pt(Le(P[1],Q[3])   ,   Le(P[3],Q[1])),
Pt(Le(P[2],Q[3])   ,   Le(P[3],Q[2]))
              ):

end: