The resisting and resonating ovoids placed in the castle ruins, together with the trees of the castle, shine brightly. The light of the ovoids and the light of the trees are autonomous, they shine brightly and then fade slowly, as if breathing.

When the ovoid is pushed, the colour of the light it emits changes and the tone unique to that color echos. The light originated from that ovoid resonates out to other ovoids and trees nearby. The tone resonates out continuously in the same way as the light, spreading throughout the ovoids, trees and all the way out to Resonating Hiroshima Castle.

If a wave of light comes from the other side of the castle, it signifies that there is another person in that location. As a result, people gain a heightened sense of awareness of the presence of other people in the same space.