[drhodes]

This is similar to how "zipper organs" work in AK Dewdney's The Planiverse, they keep 2D creatures from being separated by their digestive system. The passage that covers this concept is on page 44 which is unfortunately out of the range allowed by the publisher -> http://books.google.com/books/about/The_Planiverse.html?id=w...

[StavrosK]

Eeh, amoebas can already do it in two dimensions without a complicated system of gears that would mean they're two joined organisms anyway.

[mbq]

Amoebae have a very complex 3D structure; check out some SEM images, like http://www.sciencephoto.com/search?subtype=keywords&searchst... or http://www.photomacrography.net/forum/viewtopic.php?t=21719 . Moreover, most of their molecular machines require third dimension to work.

[StavrosK]

Sure, but if we're assuming there's life in two dimensions, the amoeba's digestive system is much simpler than zipper organs.

[mbq]

It seems so on a first glance, but if you think about how this 2D phagocyte can be formed (especially on a macroscopic scale) and how would it interact with other structures it becomes much less obvious.

[Someone]

It's easier for amoebas; they don't know about Euclidean geometry (do they know about topology, or can they have holes in their body?)