[29athrowaway]

If you like this, you might also like: Belousov-Zhabotinsky reactions

https://www.youtube.com/watch?v=PpyKSRo8Iec

https://www.youtube.com/watch?v=kw9wF-GNjqs

They can form very neat patterns.

[Synaesthesia]

Yes you can model it with a diffusion equation.