1. If I want to create a circular tower how can I "bend" the stone wall texture I have, so it can give the round shape to the building?
If not, can someone suggest a technique to create pseudo-3d walls?

2. Sometimes the icon of a tool I've selected disappears and it's replaced by a small cross. It's frustrating trying to erase something when you don't see the size of the brush.
Is it a shortcut I press that does thator something else?