Revit :: In-place Mass Pyramid Shape?

I'm following a "Simple Mass Creation" exercise in a Revit book, which says to create a cube, a sphere, and a pyramid. It doesn't say how, though, it just goes on to the next step of dividing the masses into floors. After much research and trial and error, I figured out the cube and sphere, but how the heck do you create a pyramid? At first I was thinking of a blend, from a square to a point, but that's not an option. Then I tried to use void shapes to remove parts of a cube...and I'm getting an error message because my voids are overlapping and there's no solid to cut. There MUST be a faster and less complicated way to create such a basic form.