Every time a car drives by on the bridge, its sound can be heard through this gap and then the shadow of the car passing changes the light setting and the shadows through the gap. As a result of the motion of the cars on the bridge, the light atmosphere beneath the bridge changes.
Sunlight reflects off the water of the Yarkon river and onto the walls of the bridge. The motion of the water creates different patterns of light on the bridge.
The wind which causes movement in the water can be heard in the background. The movement of the water is traced on the walls of the bridge by the light reflecting on the bridge.
The entire atmosphere under the bridge changes as a result of the dark spots and the patches of light patterns reflecting from the water.