the playground
one wave equation, and a dial for what's at the edges. play something and watch it fill the space — then change the edges and watch the same note become a completely different phenomenon.
edges absorb, nothing comes back — this is the interference case · 5.8 m across, solved on a 300×200 grid
click, or use a s d f g h j k and w e t y u. hold two for interference.
playing
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wavelength
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on this grid
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the edges swallow whatever reaches them, so nothing returns. with two sources you get the fringes from the interference page — permanent quiet lines fanning out, fixed by the geometry.
press a key to start the audio.
what's actually running
the other pages solve their case in closed form — exact, instant, and only ever able to draw the one situation they were written for. this one integrates the wave equation directly on a 300×200grid, so the boundary is just data. that's what lets a single page be four phenomena: nothing about the physics changes when you press those buttons, only what happens at the edges.
it runs in slow motion, by a lot. a stable step here is about 28microseconds of real time, and at sixty frames a second you're watching roughly 6.8 milliseconds pass per second. the note in your speakers is real time; the picture is the same note slowed by a factor of about 147.