Instructions
Build the perimeter of the base level of the pyramid. It must be a square built from standard rectangular-brick LEGO pieces. The height of your pyramid will measure about 60 percent of the length of one side. For example, if you want your pyramid to be about a foot tall, each side must be about 20 inches long. The width of each side must be at least three studs wide. If you make each side wider or fill in the entire square, the pyramid will be sturdier, but it will weigh much more and require many more LEGO bricks to build.
Build the second level of the pyramid. Build this level indented two studs within the base level, continuing to use standard rectangular-brick LEGO pieces. This will make the length of each side four studs shorter than the base level. Because the perimeter of the base level was at least three studs wide, you can attach the second level by overlapping it with at least one stud around the entire perimeter. The second level must also be at least three studs wide.
Continue building higher levels of the pyramid until you reach the focal point. Indent each level two studs within the previous level, such that from a profile view, you will see steps going up the side of the pyramid. Each step is one brick tall and two studs long. Build each level at least three studs wide, until you get to the top one or two levels, which will necessarily be smaller.