\documentclass{standalone} \usepackage{luamplib} \usepackage{dwmpcode} \mplibtextextlabel{enable} \begin{document} \begin{mplibcode} vardef acosd(expr a) = angle (a, 1 +-+ a) enddef; numeric r, phi, theta; phi = 0.61803398875; r = phi**phi; theta = acosd(1/2(1/r + r - r * r * r)); vardef dragon(expr a, b) = if abs(a-b) > 1: save p; pair p; p = r[a, b] rotatedabout(a, theta); dragon(a, p) & reverse dragon(b, p) else: a -- b fi enddef; beginfig(1); path p; p = dragon(origin, 518 right); draw p withpen pencircle scaled 1/8 withcolor \mpcolor{carrot}; picture base; base = image( draw 10 left -- 90 right withcolor 3/4; path a; a = (origin -- r * dir theta -- right) scaled 80; draw a; for t=0 upto 2: draw point t of a withpen pencircle scaled 2 withcolor .54 red; endfor label.ulft("$r$", point 1/2 of a); label.urt ("$r^2$", point 3/2 of a); label.bot ("$1$", 1/2[point 0 of a, point 2 of a]); label("$\theta$", 18 dir 1/2 theta); ); label.lrt(base, ulcorner currentpicture); endfig; \end{mplibcode} \end{document}