Walking through fluid 空間/宇宙, with the wave-like wake of his passage preceding him. Surface tension keeps him from falling through. The 石 solidity of the 洞くつ床 and somewhat leaky 天井 do help. Like a 蜂 on a waterbed at 夜, he walks without surefootedness until startled. He is not sure he can 飛ぶ.