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The worlddisks are the solid expanses in the plane of Charés where most life exists. Most worlddisks comport to a few common characteristics. They are generally round; they are usually aligned perpendicular to three "canonical axes", and they are spaced far apart from each other. There are, however, exceptions to all these rules. There exist rare "diagonal disk"s which do not correspond to any of the canonical axes--and which have life unlike anywhere else. There are irregular disks that have non-circular shapes--including the rare and mysterious "prosopoid disks" that resemble the silhouettes of humans and other creatures. There are disks that are very close, or even touching--"gear disks" that touch at the edges, and "layer disks" that are parallel to each other and overlap. (There are also some disks that touch but are neither gear disks nor parallel disks, disks of different orientations the edge of one of which touches near the center of the other, but those are even rarer than the other two cases.)

A worlddisk typically has life on both sides, though very different life on each side. Aside from having different forms and ecologies, the creatures on one side will have the opposite gravitational orientation from those of the other. Most of the worlddisks are also honeycombed with caverns, some of them quite large, and have life on the inside as well. In fact, in these interior spaces, creatures of opposite orientations often interact and intermingle.

Though they move very little relative to each other, the worlddisks are not in fact completely stationary. They tend to slowly oscillate up and down, though too subtly for most of their inhabitants to notice. This may be because the total weight on each side doesn't remain constant--if an object falls off one side of the worlddisk, then there's going to be a little more total weight in that direction, and if something falls onto the worlddisk from another, the opposite is true. (This is far from a hypothetical situation; things can and do fall between worlddisks--most notably, many worlddisks have cascades of water plummeting off their edges onto disks below, their water supplies being continually replenished by similar cataracts from other disks above.) The total balance is maintained, however, by a special material existing in the heart of the worlddisks known as antite, with the property of changing its gravitational orientation to oppose any force acting on it. Because the antite changes to counteract any alteration in the force on the disk, the total weight of the disk remains close to zero.