Pascal's Theorem

Pascal:=proc() local c,d,s,t,i,P,Q:

for i from 1 to 3 do   P[i]:=ParEllipse(c,d,t[i]):   Q[i]:=ParEllipse(c,d,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: