box -2,-2,18,8 A B C triangle 13,5,12 c1 = circle(A, B, C) D = center(c1) c2 = incircle(A, B, C) E = center(c2) F = intersection(line(A.C), perpendicular(line(A.C), D)) G = point(circle(A, B, C), arg(line(D.F)):) H = midpoint(F.G) c3 = circle(H, radius(incircle(A, B, C))) I = projection(E, line(B.C)) J = projection(E, line(A.B)) K = projection(E, line(A.C)) L = intersection(line(A.B), line(K.E)) M = projection(L, line(B.C)) draw (A.B.C) c1 0: 180: c2 c3 D.G dashed E.I dashed E.J dashed K.L dashed L.M dashed A; B; C; D; E; F; G; H; I; J; K; L end label A, C, B right A -90:; B -90:; C 0:; D -90:; E -45:; F -30:; G 90:; H 0:; I 0:; J -90:; K 90:; L -90:; M 0: E, I, B right A, J, E right E, K, A right M, L, E right B, A, C double J, E, L double B, L, M double end