Definition
Plain language
A pile of items where you only add or remove from the top.
As stated in the literature
LIFO data structure with push/pop semantics; used here as a synthetic in-context learning probe.
Also called: stacks
Why it matters: Because its rules are so simple and strict, it makes a clean test of whether a model can track state across a sequence rather than pattern-matching.
For example, a pile of plates where you can only take the one on top and can only add a new one on top.
Heard on the show
“A modern language model is essentially a stack of layers, dozens of them, and at every layer there's a shared workspace — call it a whiteboard — that every component reads from and writes to.”Episode 004 — The Sycophancy Circuit That Survives Alignment Training