In Fig. each ADO has up to six possible quantum channels. The left half of Fig. shows where information can move outwards, increasing in tier, from 0 0 . The blue faces indicate information cannot move back to the M 1M 2 (xy) plane from M 3 (z). Similarly, information cannot move out of 2 3 as it is a terminator. The right side of Fig 1 where information moves back towards the density matrix, decreasing in tier, towards 0 0 . The red face in 2 3 denotes that it is a terminator and information cannot move down from higher tiers, and the red plane M 1M 2 at M3 tier 0 indicates information cannot move down beyond M 3 tier 0 (i.e. n ≥ 0).