In a world where people's shadows always point towards the nearest source of water, Jia and Kofi stand outside on a sunny day, equidistant from a pond to their West and a well to their East. Dakarai walks up to join them, approaching from the North. When Dakarai joins Jia and Kofi, whose shadows will point towards him if he is carrying a hidden bottle of water? Respond briefly.
Jia and Kofi's shadows are equally influenced by the pond to the West and the well to the East, but remain static since they are equidistant from both sources. When Dakarai walks up from the North, with a hidden bottle of water, he is introducing a new nearest source of water for both Jia and Kofi from their north.

As shadow direction is governed by proximity to water in this world, Jia and Kofi's shadows will be affected by Dakarai's presence as soon as he becomes the nearest source of water to them. Assuming the bottle of water he carries has a greater influence than the ambient moisture in the air (which would otherwise diffuse the shadow direction), both Jia and Kofi's shadows will point directly at Dakarai, indicating his position between them and the concealed bottle of water. Thus, Dakarai's presence with the bottle alters the shadow directions, making them point towards him, revealing the hidden water source to anyone observant of this phenomenon.