Hate to be that guy, but Javascript's % is the "remainder" operator. It's just often mistaken for modulus. ;)

Hahaha, fair enough. I'll rescind some fraction of my rage.

And also fiddled with the note at the top

I don't think you need modulo, btw. Here's what I've come up with in the past (the arccos one is just for reference): https://www.desmos.com/calculator/sfc13ffxan

(or rather, you don't need the remainder operator - I think the formula is essentially modulo)

My formula can be simplified to https://www.desmos.com/calculator/pf9y0vjoep Including your parameters, default scale and offset, we end up with: ``` triangleWave2 = (period = 1, amplitude = 2) => ( x => Math.abs(x / period + .25 - Math.floor(x / period + .75)) * 4 * amplitude - amplitude ) ```

Oh that's actually quite a bit nicer to my eye! I'll replace this one with that. Thanks!