spring, source
厵 centers on the origin or starting point of something, like a spring that is the source of a stream. It represents the fundamental beginning from which something flows.
厵 is a triplication of 原 (origin, source), emphasizing the idea of a fundamental source or spring. The exact historical development is uncertain, but the structure suggests an intensification of the meaning of 原.
Three 原 (origin) stacked together amplify the idea of a source: imagine three springs merging into one powerful origin point.
For ゲン, picture the three 原 as three generators (ゲン) all powering the same source: generator -> ゲン, and the triple origin hums with energy.