By a plane partition, we mean a finite set, P , of lattice points with positive integer coefficients, {(i, j, k)} ⊆ N, with the property that if (r, s, t) ∈ P and 1 ≤ i ≤ r, 1 ≤ j ≤ s, 1 ≤ k ≤ t, then (i, j, k) must also be in P . A plane partition is symmetric if (i, j, k) ∈ P if and only if (j, i, k) ∈ P . The height of stack (i, j) is the largest value of k for which there exists a point (i,...