% This figure illustrates Morley's theorem.
% Copyright (c) Christian Obrecht 2001

A B C triangle
a = angle(B,A,C) ; b = angle(C,B,A) ; c = angle(A,C,B)
ab = angle(vector(A,B))
bc = angle(vector(B,C))
ca = angle(vector(C,A))
l1 = line(A,(ab + a/3):) ; l2 = line(A,(ab + 2*a/3):)
l3 = line(B,(bc + b/3):) ; l4 = line(B,(bc + 2*b/3):)
l5 = line(C,(ca + c/3):) ; l6 = line(C,(ca + 2*c/3):)
D = intersection(l1,l4)
E = intersection(l3,l6)
F = intersection(l2,l5)
color(lightgray)
draw(l1) ; draw(l2) ; draw(l3) ; draw(l4) ; draw(l5) ; draw(l6)
color(black)
draw(A,B,C) ; draw(D,E,F)