Stability is a local contract
A still life is a finite pattern that is already in balance. Every live cell has a survival count, and every nearby dead cell avoids the exact three-neighbor birth condition.
The block is the cleanest case: four live cells in a 2 x 2 square. Each cell sees three live neighbors, so nothing dies. Every adjacent empty cell sees either two or fewer live neighbors, so nothing is born.
The beehive shows why shape alone misleads
The beehive is a six-cell still life with an empty center. Visually it looks as if the hole should fill in, but the rules say otherwise. The center does not have exactly three live neighbors, so it stays empty.
That is a useful teaching moment. Life patterns are not governed by outline, symmetry, or what the viewer expects. They are governed by neighbor counts at every tick.
Stable objects do work in active reactions
In larger Life constructions, stable objects are not background decoration. Blocks and beehives can absorb debris, bound reactions, or take part in eater-like behavior when placed with care.
This is why a serious pattern catalogue spends time on still lifes. They are the punctuation marks that let active reactions become readable circuits instead of one-time explosions.
Working takeaway
Try the block, beehive, and loaf in the lab. The useful habit is to inspect the empty cells around the object, not only the live cells inside it.