31. Well-heeled mothers and their Filipino au pairs play with children near the famous water clock there. 32. Some modern timepieces are called " water clocks " but work differently from the ancient ones. 33. The bronze heads were part of a water clock featuring the 12 animals of the Chinese zodiac. 34. Some water clock designs were developed independently and some knowledge was transferred through the spread of trade. 35. The Zeebad Gonabad water clock was in use until 1965 when it was substituted by modern clocks. 36. At the centre of the pedestrian mall is a large water clock sculpture, designed by Victor Cusack. 37. The Zeebad Gonabad water clock was in used until 1965 when it was substituted by modern clocks. 38. The explanation of a " clepsydra " or water clock was a popular topic in the Middle Ages. 39. The frequency source for the first nonsolar timepieces, water clocks , was a steady drip into a catch basin. 40. Water clocks or clepsydra measure a gain or loss of water by using drops of uniform size and frequency.
