The watercourse is visible the moment visitors pass through the entrance to the Taj Mahal complex, as it provides a shimmering path leading directly to the Taj Mahal itself. The watercourse consists of four long pools, each adorned with lotus-shaped fountains. The four converge on the reflecting pool midway between the entrance and the plinth or platform upon which the Taj Mahal rests. The watercourse not only forms a dramatic foreground to the Taj Mahal, it also has a symbolic and architectural function, that of dividing the pleasure garden into four equal quadrants (the pools are laid out on the cardinal points of the compass) an essential theological and aesthetic feature of Mughul gardens. Water from the gardens is taken from the nearby Yamuna river, where it was once pumped in by a hydraulic system driven by oxen. The water is stored in tanks and then distributed to the four pools. One ingenious feature of the watercourse system are the bulbs containing water below each of the fountains. Water flows independently into each bulb and from there is forced into the fountain. This arrangement ensures that the pressure of the fountains is uniform, and does not diminish from one end of the pool to the other. The overflow from the fountains is used to irrigate the gardens proper.