If the illustration below is meant to show multiple layers then I'd consider annotating the axes. At least to me it's not immediately apparent how the image correlates to "every tile is covered by two tiles above it"

Is this clearer?

Tbh, I'm still not convinced that the illustration meaningfully adds to my understanding. I would consider only showing pairs of layers and flipping the axes, but the interactive chart further blow might still do a better job at conveying the idea.

Does this help with making the connections visible?

Is the point grid discrete? If so, would make sense to snap the dot to the grid?

The way I generate these points produces integer grid values. But typically these pmj02 sequences are generated as floating point values.

It might be neat to show a single plane in which all tiles touched by a point are highlighted 🤔

When working with ImageData you need to pass a devicePixelRatio of 1 to DOM.context2d to disable scaling, although I'd recommend to just create the canvas and context yourself instead.