fof(goal, conjecture,(![L1,L2,A,B,C]:((line(L1)&line(L2)&int_l_l(L1,L2)&point(A)&inc_po_l(A,L1)&inc_po_l(A,L2)&point(B)&B!=A&inc_po_l(B,L1)&point(C)&C!=A&inc_po_l(C,L2))=>(ncol(A,B,C))))).
