d = 7 (slider from 1 to 15, step 1)
L = Sequence(Sequence[Sequence[If[(k + 0.5 - d / 2)^(2) + (l + 0.5 - d / 2)^(2) + (n + 0.5 - d / 2)^(2) ≤ (d / 2 - 0.25)^(2), Cube[(k, l, n), (k + 1, l, n), (k + 1, 1 + l, n)]], k, 0, d - 1], l, 0, d - 1], n, 0, d - 1)