This is no XY, because it does not use the sprite's X or Y positions at all. It is one line, because it computes the pen color entirely in one line with no variables/lists.
Inspired by @kc021's "No XY: 1 Line Challenge": https://scratch.mit.edu/projects/442729671/. I worked out all of the math myself for this (https://u.cubeupload.com/Piano_miles/Triangulation.gif), but the idea of using the sprite distances rather than the XY positions entirely goes to @kc021! Quite a clever twist that made things more fun, both in the triangulation math and in the code, but now I have homework to finish since I did this instead of homework. Hehe.
