retest for screenreader-only a11y (WASD?)

[hchiam]

1. • make a arrows/"WASD" keyboard control demo
2. • test with a screen reader

[hchiam]

make sure to make the instructions element have role="alert" (and maybe aria-live="assertive")

[hchiam]

once this is done, move on to #14

[hchiam]

https://medium.com/@ckv214/drawing-with-sound-4d807a03d8e2