Yes, I wanted to reuse Factor Crafter's core concept and art to make something with more gameplay to it. I knew I wanted each n-stone to cost n currency and have all abilities of its factors. I originally considered Tower Defense, but it was hard for composites to be worth their cost. To make something like 11x5 be worth spending 55 currency on, I needed players to have limited stones per turn. This lead me to use cards. (Also I play a lot of card games.)