paper 100 antialias 1 command griddify_normal { pen (100 -<time 4>) repeat n 0 9 { line 0 50 50 (5+10*n) line 50 (5+10*n) 100 50 line 50 0 50 100 } } command griddify_time { pen <time 4> repeat n 0 9 { line 50 0 (5+n*10) 50 line (5+n*10) 50 50 100 } } forever { griddify_normal griddify_time }