oh, and the sprite sheets of the letter tiles do not match. the xml says they are 256², but in the sprite sheet the images are actually 257 wide and 258 tall, resulting in 1031 pixels of the texture (width of 4 tiles) and not 1024. graphics do not match the xml definition.
There are also some ghost-pixels at the right and bottom edge of the combined atlas png (at least for the wooden tiles)