Speaking of awkward Sega architecture, MattKC recently did a video[1] on his second channel about the 32X, which if you don't know was a weird module that slotted into the cartridge slot of the Genesis to enable it to play a separate lineup 32-bit games.
Since it was essentially 2 consoles working in tandem, it was another situation where you had 2 CPUs working together to pump out a video image. He tried to wire up his own video cables and found you could cut out the video signal from one machine and only get the output rendered from the other. The 32X itself would pump out 3D rendering while the Genesis would supply 2D graphics for e.g. menus, HUD, sprites, etc.
Since it was essentially 2 consoles working in tandem, it was another situation where you had 2 CPUs working together to pump out a video image. He tried to wire up his own video cables and found you could cut out the video signal from one machine and only get the output rendered from the other. The 32X itself would pump out 3D rendering while the Genesis would supply 2D graphics for e.g. menus, HUD, sprites, etc.
[1] https://www.youtube.com/watch?v=rl9fjoolS2s