Brick by Brick - The number, in each brick in the 4-sided pyramid, is the sum of the numbers in the two supporting bricks, working from the outside in or from the base to the apex of the pyramid. We've filled in a few bricks to get you started. Find the number that goes in the very center or top brick which is the sum of its four side bricks. Note: Each number in the shaded bricks is the sum of the two adjoining bricks as shown by the direction of the arrows.