Patents are entirely unrelated to trademarks. I very much doubt that an operating system would be able to infringe on a patent for interconnecting plastic blocks.
An operating system called "LegoOS" might infringe on the trademark of a plastic block company called "LEGO" (though one of the tests is "likelihood of confusion" and it would be hard to confuse the two).
An operating system called "LegoOS" might infringe on the trademark of a plastic block company called "LEGO" (though one of the tests is "likelihood of confusion" and it would be hard to confuse the two).