This antique "yachting piano" was designed to fit into small apartments--or elegant motor yachts. Its keyboard folds up vertically and clips into the piano itself for sleek storage and the music stand pops into the piano's hinged lid. 3 keys are omitted at each end to streamline the instrument.
Photos attached show piano 1) open with music stand, 2) closed with music stand folding accordion-style, and 3) closed with the music stand hidden inside the lid.
Sold by Selfridges, London around mid-century, and made by Supertone Pianos, it is in good working order as an instrument.