PressPull   

		The PressPull tool is used to edit a single face of an object after it has already been created.  This can be used to extend or shorten the side of a block or any other 3D object. To use the tool, select the surface you want to move.  As you hover over the surface, the edges will become dashed to show which side will be selected.  Click to accept that side as the one you wish to change.
		You can now move this side around to wherever you want.  You can either drag the mouse around in model space to move it to where you want it, or you can enter a value via the keyboard.  A positive value will move the face outwards from the existing object, and a negative value will move the face inwards from the existing object.
		Once you are finished, the block will still be one solid object.