WAP enabled phones (the early mobile internet protocol of the early 200s, using a card metaphor) tended to have elongated pixels as well. Converting images for this was fun!

(WAP used a special, binary image format, but the compiler for this didn't care about pixel ratio. The fun part was really designing and previewing these images on square-pixel hardware and then converting this to something which was still crisp on the actual hardware target. But then there were also PDAs, which did have square pixels…)

Fascinating. But how does the graphics card know the pixel layout of the display or is there a chip in the display that recomputes where to display a pixel at (3,3) for example?