Encode the speed of light, 299,792,458 m/s, into a peg chain.

299792458 → 29 97 92 45 8 → knob, book, pawn, railway, ivy.

The story: in a beam of light, a brass door knob sits on a book; a chess pawn slides down a railway wrapped in ivy.

Nine digits → four pairs plus a leftover:

• 29 = knob, 97 = book, 92 = pawn, 45 = railway, and the lone 8 = ivy (/v/).

Story: a brass door knob sits on a book, a chess pawn slides down a railway wrapped in ivy. Decode the consonants and you get 299 792 458 — the exact metres-per-second light travels in a vacuum.