Press space to toggle between moving the light source around (it follows the mouse cursor) and locking it in place. Press r to randomize circle locations and radii.
The other night I stumbled across a video talking about doing raytracing on a TI-84 Plus CE (Silver Edition? I'm not sure), and something about it got me wondering if I could maybe try and implement ray marching on one. I don't have much of any experience with ray marching though, aside from having seen a couple YouTube videos about it, so I figured I'd start smaller and work my way up!
