''A very useful conveyor piece that allows for complicated conveyor routes.''
The Conveyor Corner is conveyor that bends around a corner. This piece takes up a ridiculous amount of room; you can accomplish making a corner with any conveyor without walls. However, ores can get stuck by doing this, so some users use this item instead. This item has another counterpart, the Reverse Corner. It can be used to turn ores the other way.
This will possibly be retired/removed from the game soon.