This produces really nice output. I love the slow-moving icy little berg. I know you said you weren’t implementing collision detection here, but I thought I’d drop this useful link in case you’re interested later. It’s for Processing, but could be ported to p5.js (or maybe someone’s already done it). Here is the point/triangle collision detection algorithm.
someone has definitely done it but I felt inspired to take on the challenge. Here is my implementation of the algorithm (adapting the example)