bottommost

The topmost and bottommost segments were congruent, and their product was 2−√2.

Of these six permutations, Fetch and Fitch bit the same color in four of them — when Fatch was either the topmost or bottommost bite.

When this was greater than 1 or less than -1 — that is, beyond the extent of the bottommost block — the tower would collapse.

The bottommost layer adjusts its synaptic weights to minimize its error, based on the sensory information it receives.