Picture two fences with a gap between them, or two armies dug in facing each other. The ground in the middle has no owner written against it. Neither side farms it, guards it or tidies it, because claiming it would mean crossing into the other side's view. So it stays empty — not because it is useless, but because it belongs to nobody. Lift that gap off the map and drop it onto ideas, jobs or ages, and you get the second use: the space between two things that neither of them claims.
可以想成：兩道圍籬中間隔著一條空地，或是兩支軍隊面對面挖好陣地，中間那塊地誰也沒登記。兩邊都不耕、不守、不整理，因為一走進去就等於踩進對方的視線。所以它一直空著——不是因為沒用，而是因為不屬於任何人。把地圖上這條空白帶抬起來，放到想法、工作或年齡上，就長出第二個用法：兩樣東西中間那塊誰都不認領的區域。
登入就可以看每一支怎麼連回核心畫面。