[MissC]

Or perhaps we could consider the organisms in the animal kingdom that have a dual set of characteristics so to speak. For instance, lungfish can obtain oxygen from both the air and the water. Whales have fins and tails like fish do, but they still breathe oxygen from the air like every other mammal.

In permaculture, in-between is a useful feature. "Margins" is the term -- the new and vibrant ecosystem that emerges where two differing ecosystems meet, such as shorelines (ocean/land) and savannas (forest/plain). Margins are kinda both, kinda neither, and a whole new thing at the same time.

Knowledge certainly begets metaphor, doesn't it?!