I've tried doing the same and I believe each tile looks as if it is 4 tiles. In other words, it's an illusion based on the look of the tile (4 sections on a tile), lighting, etc.
Long-time lurker to the forums, but new subscriber. Love what you've done with the floor and I am looking to do something similar.
How many square feet is your garage? And do you have any pictures with your cars in it? (My garage is about the same size as your garage.)