I think they are just going to offer it as open source software be a use you can get the Lego yourself. The software scans the picture and translates that to calendar input.
the last line on the post says it is an experiment and not a product.
Unfortunately, open source vs. commercial has nothing to do with whether something is a trademark infringement. The countless open-source fanworks taken down by brand-owning companies are a testament to this. As long as lawyers believe that "if you don't defend your trademark with takedowns, you'll lose the ability to defend it in court," then benign derivatives will not be able to use IP without licensing it in the general case.