https://docs.google.com/presentation/d/1mQeB9WefmybyNMqfLKw_3yDIqZSp5RYjGZOxtzj8_Jk/edit#slide=id.g2a0da7e5a25_0_70
prototype: https://editor.p5js.org/sirui/sketches/zsalb4C9z