I liked @Layzej's pen-based ripple effect, so I thought I'd have a bit of fun and add some real-time interaction with the mouse. >> WARNING: you need a decent computer for this to work well! << Try it on phosphorus: https://phosphorus.github.io/#62815354 Move mouse around to disturb the water (ripples die away if you keep mouse still). Hold down mouse button to make bigger ripples - it's also then continuous (so it won't die away). It uses a basic finite-difference method to solve the wave equation. See https://en.wikipedia.org/wiki/Finite_difference_method Each pixel of the picture corresponds to a point on the finite-difference grid. When the mouse is moved (or button pressed), it injects a 'disturbance' into the grid-points along the path of mouse movement (roughly), which then travels through the grid.
