REPL limitations:
- poor feedback loop between coding and execution (re-loading code etc.)
- limited to text
We can use special tooling to interpret returned structures as image graphics. e.g. we can recurse to create fractals.
Animations leverage a games/animations framework called SpriteKit (from Apple)
He walked through creating Flappy Bird using his own snippets in ~15 minutes! This was incredibly cool. The overall environment was defined with something like a map of SpriteKit keys to lambdas.