Uids with the '.' character throw off the tiling logic.

The tiling logic is hard coded to split a field containing the uid and take [1:3]. If the uid includes a '.' character, the tiling logic is broken by this case.

Suggested solutions:
* Specify the range to take the tiling values from based on a relative-to-end specification, eg [-3: -1] (change to clodius).
* Reject user defined uids that contain the '.' character or other sensitive characters from the tiling logic.