readme.md

carrier wave

Three stones dropped in a pond, rendered by a terminal.

what you're looking at

Three points drift around the screen, each sending out rings. Where two crests meet they add up; where a crest meets a trough they cancel. That is interference, the same thing that makes noise-cancelling headphones work.

The picture has only ten brightness levels, because it has only ten characters: .:-=+*#%@. The pink marks the rare places where all three waves agree.

things worth stealing from the prompt

Giving the exact ramp. Left alone, agents pick long 70-character ramps that look like mush at this size. Ten characters keep the bands crisp.
"Correct for that so the ripples are round." Character cells are not square. Naming the trap up front saves a round of "why is it squashed?"
Saying what the focus is. "These pink crests are the focus of the piece" tells the agent which effect must survive if something has to give.

try changing

one source instead of three (clean rings, no interference)
a ramp made of box-drawing characters or a single word
tie one of the sources to the pointer

Make a single self-contained HTML file: a full-window canvas artwork called "carrier wave". No libraries, no controls. The whole window is a grid of monospace characters on black, about 110 columns' worth of cells across the longer side. Nothing is drawn except characters. Three invisible points wander slowly around the grid on looping paths. Each one sends out circular ripples, like a stone dropped in water: a sine wave of the distance from the point, moving outward over time. At every cell, add the three ripples together. Turn that sum into a character using this brightness ramp, from empty to dense: .:-=+*#%@ (the first character is a space). Low values are blank, high values are heavy glyphs. Brighter cells are also more opaque white. Where the three waves pile up and the value is in the top 14%, draw the character in hot pink (#ff4fd8) instead of white. These pink crests are the focus of the piece: thin arcs that appear, slide and vanish where ripples cross. Monospace characters are taller than they are wide. Correct for that so the ripples are round, not oval. Handle window resize and high-density screens.