I would create the base pyramid by using a cloner in grid mode that's dense enough to fill the pyramid. Then I'd create a pyramid object that fits inside the grid. Next, use a volume effector with the visibility parameter checked, and drag the pyramid into the object link box.
That will give you the basic pyramid shape.
To build the pyramid up (or down) I'd use a plane effector with the scale parameter set to -1. Set the falloff mode to linear and falloff amount to 0. Then animate the effector's position to build up the bricks.
I have done this in such a way the building of it is able to animate. I made square splines, cloned vertically with shape decreasing as gets to the top. I made sure they were spaced so that vertically, my brick sizes would match and they would stack nicely without much intersection. After I set my splines carefully going up, I connect/delete object command them and now I have one spline, but non continuous representing my skeleton of the pyramid. After this you use the mograph cloner in several ways depending on what works best and you can then keyframe the thing so it animates like it is being built. It's not perfect but it was all I could come up with for a client on short notice who really wanted the depiction of a building pyramid. It was rendered to look like vector art using sketch and toon and flash export. Those vectors were then preserved and moved into AE for nice clean edges throughout post. Strange workflow but it did the trick. Sorry I can't post here because it's corporate/internal.