Click pegs to toggle. Active pegs trigger automata events at each hour.
Ismail al-Jazari, the father of robotics, described this extraordinary water-powered clock in his "Book of Knowledge of Ingenious Mechanical Devices." It stood over 11 feet tall.
The clock featured programmable automata: birds that dropped balls into cups, musicians who played, doors that opened to reveal figures, and a zodiac disc that rotated with the hours.
The drum with pegs is considered one of the earliest examples of a programmable machine — a precursor to the music box and even the computer.