I created this wedge by translating the cube along the x axis. I then deleted the two edges on one of the remaining square sides (as opposed to the 4 rectangles that were created by the translation). This left only the 2 rectangles on the top and bottom and one remaining square. Taking the edge hanging in midair off the top rectangle, I then translated the top edge to the bottom edge and created faces from the now 3 vertices on both sides.
