Randomize Equation Button

[jeffeb3]

Similar to @msurguy's flow lines randomize button: https://msurguy.github.io/flow-lines/, it would be neat to have some random equations for scale and spin to make a lower barrier of entry to editing the functions.

Original comment from Maksim:

Would be cool to have Randomize button for scale and spin. I got my randomizer from @anvaka's repository here: https://github.com/anvaka/fieldplay/blob/master/src/lib/generate-equation.js , here's my take on it, with math.js functions: https://github.com/msurguy/flow-lines/blob/master/src/lib/function-generator.js