Before and after
I like the dedication :) However, just to keep your sanity: you don't really need to use only Park Pods for maximum happiness. All houses other than the basic House have an upgrade (or multiple) boosting them to 100 happiness, normally involving computer chips. The Modern Rustic Home also needs to be adjacent to three other rustic homes/parks for that.
This all doesn't mean a city with only Park Pods wouldn't be cool and interesting, of course. :)
There's no real limit! Except that numbers on computers have a limit (at least the type I use), so that would be it. But the game would behave weirdly and probably run way too slowly long before you reach that. I just tried stacking 10,000 buildings (not manually, I'm not crazy :P). That works fine, except that my browser doesn't want to save a screenshot then anymore.
also are u going to update the coolmath version anytime soon?