This model consists of just a 2-cube thick hull of a pyramid. This makes it possible to create a larger model with fewer modules than in the case of
a completely solid model. As one can easily show, the general formula for the number of cubes in n-th level (with a single cube being level 0) is:
N(n) = 8n-4 for n ≥ 2
5 for n = 1
1 for n = 0
Thus, the number of cubes in the whole pyramid hull of height m (when a single cube counts as a pyramid of height 1) is, for m ≥ 2:
1+5+Σm-1i = 2(8i-4) = 6 + 4(m-1)2-4 = 4(m-1)2 + 2
Compare also with the meshed pyramid.