path h[], snake;
h0 = for i = 1 upto 6: dir 60i -- endfor cycle;
for i = 1 upto 6:
h[i] = h0 shifted (point 0 of h0 - point 2 of h0) rotated 60i;
endfor
snake = point 0 of h3 -- point 1 of h2 -- point 2 of h1
-- point 1 of h6 -- point 2 of h5 -- point 3 of h0
-- point 1 of h4 -- point 0 of h5;
snake := snake shifted - point 0 of h3;
snake := snake rotated - angle (point 0 of h5 - point 0 of h3);
snake := snake scaled (1 / length (point 0 of h5 - point 0 of h3));
vardef rattle(expr level, a, b) =
if level > 0:
save s; path s; s = snake zscaled (b-a) shifted a;
reverse rattle(level - 1, point 1 of s, a) &
rattle(level - 1, point 1 of s, point 2 of s) &
rattle(level - 1, point 2 of s, point 3 of s) &
rattle(level - 1, point 3 of s, point 4 of s) &
reverse rattle(level - 1, point 5 of s, point 4 of s) &
reverse rattle(level - 1, point 6 of s, point 5 of s) &
rattle(level - 1, point 6 of s, b)
else:
a -- b
fi
enddef;
beginfig(1);
pair a, b; path s;
a = 124 left; b = 124 right; s = rattle(4, a, b);
fill s -- b + (40, 0) -- b + (40, 224)
-- a - (40, -224) -- a - (40,0) -- cycle
withcolor 3/4[1/4 blue, white];
endfig;
\end{mplibcode}
\end{document}
