An oft-repeated type, since the times of the Marquis of Worcester. This type has been made with many sections, each section advancing a step in order to overcome its propensity to find a balance and an excuse for stopping.
(Subsection 917, from p.366)
From: Gardner D. Hiscox, M.E., Mechanical Appliances and Novelties of Construction (1927), Norman W. Henley Publ. Co.