% equilatrianglelines.mp % L. Nobre G. % 2009 prologues := 1; beginfig(1); numeric u, factordown, ang, angl, angh, ydown, xl, xh, astep; pen pendot; path uline, rline, dline; pair auxp; u = 2cm; factordown = 2.34; astep = 2.75; xl = -2u; xh = 10u; angl = 7; angh = 38; pendot = pencircle scaled (2.5mm); ydown = -u*factordown; uline = (xl,u)--(xh,u); rline = uline rotated (-60); dline = (xl,ydown)--(xh,ydown); draw uline; draw (xl,0)--(xh,0); draw dline; draw rline; z1 = rline intersectionpoint dline; draw z1 withpen pendot; draw origin withpen pendot; for ang=angl step astep until angh: pair uapex; ypart uapex = u; uapex = whatever*dir(ang); auxp := uapex+abs(uapex)*dir(ang-120); draw origin--uapex--auxp--cycle; endfor; endfig; end.