A strange attractor that will not sit still
Two trigonometric maps, iterated: it never escapes, repeats, or settles.
Take a point, run it through a pair of sine and cosine formulas to get another point, and repeat forever. That is the entire rule. The point never flies off to infinity, never lands back exactly where it has already been, and never settles anywhere — it endlessly wanders a shape it cannot leave, which is what the word attractor means here.
That shape has a fractional dimension: more than a line, less than a surface. Nobody draws it and it is not stored anywhere, it is simply the set of places a wandering point is permitted to go. Nine hundred points wander at once and the canvas counts how often each pixel is visited, so brightness is really dwell time — the bright filaments are where the system lingers longest.
For any fixed set of constants the figure is a still image, which is why two of the four drift on slow waves of different lengths. Because those lengths never come back into step, the form folds and reopens without ever quite repeating itself. Set drift to zero and it freezes into a single figure you can sit and study.