It's all in the animation :) When they combine to form Mighty Orbots (that was the name of the giant robot, I kid you not - it was *not* the collective name of the bots themselves as is usually assumed and popularly believed), their faces and features stretch and distort will all you can really see of the original bot (which were originally called "Broots" in the super-rare pilot episode) is the color scheme. This means that they're made at least *partially* from a super-malleable alloy and/or gazillions of Nanobots :)