Early fountains depended on the natural gravitational flow of water, from a spring or channel supplied by a distant and higher source of water, which provided hydraulic head. While some other early fountains were geometrically regularized springs which were developed in the classic Persian garden. These gardens were designed to provide relaxation. They were typically enclosed. With regard to the structural aspect of the Persian garden design, the effect of sunlight was the main concern. Shapes and textures were specifically chosen for their ability to direct sunlight. In the 16th century elaborate fountain displays were garden features of Mannerist gardens of Central Italy and the Mughal gardens of India. Early Modern English employed fountain to refer to a natural spring water or source, which the 16th century garden fountain might consciously imitate in a grotto. In modern times, a spouting fountain designed by a certain Tim Clemen and Murase Associates and installed in August, 2000 replacing a 1965 fountain at a park in Portland. Programmable nozzles and valves on several plumbing loops were built creating a playful atmosphere of surprise trajectories and timing sequences. This is the Holladay Park Fountain at Holladay Park at NE 11th and Multnomah.