The reason we take the corners off the tiles is because we’re working with a curved bay. If we didn’t, watch the video to see what happens — you can see here where the shoulder hasn’t been removed compared to this one where it has. On the one where it’s still on, there’s a gap on just that single tile. Look at it next to the other one — nice and tight. By removing the shoulder, we’re able to bring the tiles closer together for a much neater finish.