You could solve this with the Add2 command (there is an Add2 command at line 5 of your script). The values (x, y) will need to be parametric depending on the desired size and the Mul2 values. It will take a bit of thinking and math to get the desired result. Going from a single drawn object to a parametric one is not simple, so this is why I prefer to code it.
David Maudlin / Architect
AC 22 - Mac OS