I paid the $4 and got it. Slick & entertaining. Not as hard-core math-ish as I'd like, but fun to zoom around in. There's in-app "pro upgrade", which I find a b

I paid the $4 and got it. Slick & entertaining. Not as hard-core math-ish as I'd like, but fun to zoom around in. There's in-app "pro upgrade", which I find a bit irritating if that's where the greater numeric control & deeper resolution resides.