The first known geared clock was invented by the great mathematician, physicist, and engineer Archimedes during the 3rd century BC. Archimedes created his astronomical clock that was also a cuckoo clock with birds singing and moving every hour. It is the first carillon clock as it plays music and simultaneously with a person blinking his eyes surprised by the singing birds. Archimedes clock works with a system of four weights, counter weights, and strings regulated by a system of floats in a water container with siphons that regulate the automatic continuation of the clock. The principles of this type of clocks are described by the mathematician and physicist Hero, who says that some of them work with a chain that turns a gear of the mechanism. Another Greek clock probably constructed at the time of Alexander was in Gaza, described by Procopius. The Gaza clock was probably a Meteoroskopeion, i.e. a building showing the celestial phenomena and the time. It had pointer for the time and some automations similar to the Archimedes clock. There were 12 doors opening one every hour with Hercules performing his labors, the Lion at one o'clock, etc, and at night a lamp becomes visible every hour, with 12 windows opening to show the time.