Eureka Crate Build Your Own Perpetual Calendar

Construct the date and day-of-the-week tumblers, add the month dial, then put them all together using a marvelous mechanism called a Geneva drive. Explore the evolution of perpetual calendar design, then read about some kooky calendar calamities through the ages (from skipped leap years to the Y2K bug)! Great gift for S.T.E.M learning. New in box