The one-horse shay is a light, covered, two-wheeled carriage for two persons, drawn by a single horse. It is the American adaptation, originating in Union, Maine[1], of the French chaise, and is also known as a whisky as its owners tended to whisk about doing errands. The body is chairlike in shape and has one seat for passengers positioned above the axle, which is hung by leather braces from wooden springs connected to the shafts. It is colloquially known as a one-hoss shay.
Oliver Wendell Holmes, Sr. memorialized the shay in his light poem "The Deacon's Masterpiece or The Wonderful One-Hoss Shay". The fictional deacon built this wonderful one horse shay so it wouldn't break down. He built it from the very best of materials so that each part was as strong as every other part. In Holmes' humorous, yet "logical", twist, the shay endures for a hundred years to the day (actually to the moment of the 100th year of the Lisbon Earthquake — to the precise hour of the earthquake shock) then it "went to pieces all at once, and nothing first, — just as bubbles do when they burst." It was built in such a "logical way" that it ran a hundred years to a day.
In economics, the term "one-hoss shay" is used, following the scenario in Holmes' poem, to describe a model of depreciation, in which a durable product delivers the same services throughout its lifetime before failing with zero scrap value. A chair is a common example of such a product.[2]