/*Source*/ import Lsystem; size(8cm,0); Lsystem HilbertCurve=Lsystem("X", new string[][]{{"X","-YF+XFX+FY-"},{"Y","+XF-YFY-FX+"}}, La=90, Lai=0); HilbertCurve.iterate(6); draw(HilbertCurve.paths(), linewidth(1bp)); shipout(bbox(Fill(lightgrey)));