Folk på fällan av Ian Watson.
Historien var presenterad i samlingen Evil Water: And Other Stories . Delar av texten finns i Google eBook-versionen .
Den vertikala väggen beskrivs enligt följande:
"Just suppose," he said, as the daylight dimmed, "that a whole world is as flat as a leaf! And suppose that creatures live within that leaf, who themselves are perfectly flat. Imagine this narrow ledge here simply carries on" - he chopped his hand into empty space - "in that direction forever! Imagine that it is a simple, infinite surface with nothing above it and nothing below it. And with no precipice to jut out from."
Och senare, en karaktärs förslag att klättra uppåt verkar vara en stor sak jämfört med vad som vanligtvis görs:
"We make daily forays up and down for food. When we've scalped a patch we migrate sideways. That's life."
[...]
"And you'll die clinging on. Or rather, you'll die pretty soon after you stop clinging on. Now, today I'm climbing up to the Chief-of-Chiefs for that conference. Bounce will guard our ledge and keep the kids tied up. Loosepiton" - that's me - "will escort me upwards."