SCREEN.CONSOLES.snes spread into createGame: 256 × 224 pixels, 60 pictures a second, and pixels 8:7 (pixelAspect), a little wider than tall, as a 4:3 television showed the NES and the SNES. With scaling: 'integer' the rows stay a whole multiple and the columns take that times 8/7: the television's shape exactly.
The artists of the time drew for that television. The green disc was drawn for it, an eighth narrower than tall in pixels, and with the television's pixels it is round; the yellow one was drawn for square pixels. Press T to switch the shape (useGame().setPixelAspect): only the size on screen changes, the game draws the same pixels. C puts a crt() on top, which hides that the columns are not all the same width.