My 7yo DS has a Gravitrax starter set which he loves. He particularly enjoys following instructions to build the different routes. He is less keen on making up his own. I want to get him some 'expansion' bits e.g. the ski lift or catapult one. Does anyone know where you can find instructions of how to build more routes using different pieces? I don't mind if it's official or YouTube style. He also has Marble Rush and liked they have more builds online and specific builds you can make by mixing sets. This influenced which sets he wanted to buy, so he could combine them. I'd love something similar for Gravitrax but not got far with Internet searches.