u = 0.57cm; beginfig(1); pair A, B, C, M, N; A=(0,0)*u; B=(-0.75,-3)*u; C=(1.5,-3)*u; M=(0.25,1)*u; N=(-0.5,1)*u; draw (-0.8,1)*u--(1,1)*u withpen pencircle scaled 1pt; draw (0.5,2)*u--(-1,-4)*u withpen pencircle scaled 1pt; draw (2,-4)*u--(-1,2)*u withpen pencircle scaled 1pt; draw (-1,-3)*u--(2,-3)*u withpen pencircle scaled 1pt; label.lft("A",A); label.urt("C",C); label.ulft("B",B); label.lrt("M",M); label.llft("N",N); label.rt("(d)",(0.5,2)*u); label.lft("(d')",(-1,2)*u); endfig; end