Think outside the BOX! Try a WEDGE!
You can create a 3D solid wedge similar to creating a box. Begin by drawing a rectangle and then specify the height. However, keep in mind that when drawing a wedge, the first point you pick determines which side of the wedge will have height!
After you create the wedge, you can easily edit it using grips, similar to a box. You can edit the overall height of the wedge by stretching the top or bottom triangular grips and you can edit the width or length using the four triangular grips at the base of the wedge. The four square corner grips enable you to stretch the corners of the wedge to edit the length and width at the same time! You can use the square center grip to move the wedge without changing its shape!
In addition to editing the wedge with grips, you can use the Geometry pane of the Properties window to enter values for the length, width, and height of the wedge!