they're called print bricks and they're default
http://forum.returntoblockland.com/dlm/viewFile.php?id=102This?
Its not prints. Its just a brick that say No Line brick (Not printable).
That's in One Random Brick Pack, I think....
Do you want something like blank brick textures for all bricks, if so, you can find that here: http://forum.blockland.us/index.php?topic=242113.0Just scroll down a bit