You know when you see the representation of the x, y, z axes for Cartesian co-ordinate system. You can make the symbol with your fingers, like you're at a heavy metal concert. I need to make quarter round meet on the inside of a closet. The trim goes up the inside laying vertically on the 90° corners, and the same trim also meets going laying horizontally both left to right and front to back. To trim out the top square of whiteboard, which is the ceiling of the closet, and the peg board, the three sides. I know how to cut a 90° corner from the same trim to do the back of a closet, but how to put a third piece "normal" to those. Can you cut all 3 at an equal angle, or do you have to cope one(s) into the other(s)?
p.s. The quarter round isn't just plain quarter round. I made my own. I took a 3/8" beading bit to 1/2" x 1/2" plain quarter round, for a little more class. Leaves a 1/16" lip. More or less the same idea.