I've seen several masonic lodges not too far from my place with their logo imprinted on the buildings. Apparently, the letter G stands for Geometry under the Great Architect of the Universe. I suppose anyone can enter since it's in the public eye but assuming there will be prerequisites possibly fees before joining. I even wanted to enter myself but I didn't. Strangely enough the place looked empty. No cars or anyone outside the lodge. But I did a quick google search on what to expect within the building - assuming they're all similarly designed - the images I've seen reminds me of a ceremonial room to conduct rituals.