Peacock-shaped Hand Washing Device: Illustration from The Book of Knowledge of Ingenious Mechanical Devices (Automata) of Inb al-Razza al-Jazari (recto), 1315. The Arabic title of this work is Kitab fi marifat al-hiyal al handasiyya (The Book of Knowledge of Ingenious Mechanical Devices). According to the description of the device illustrated here, the peacock is filled with water: as it flows into the vessel below, it raises a float that opens a door in the section above, causing the little figure to move forward offering soap; as more water flows, a second door will open and another figure will move forward offering a towel. Finally, the dirty water is drawn off by means of a spigot.