I don't know how useful it will be but maybe it helps in level 5.

This is known and sadly I have not been able to find any use for it. The texture is just too tall to be able to reach the red brick and it cant be used to get a good cycle on the cauldron.

All textures like it can be clipped through if you enter from the side of it. This knowledge is currently used in level 4 and 10.

Good find and please keep posting any finds :)