A Thceyn birthing takes the inverse shape of ours. A new Thceyn forms as a thin, flexible membrane around the Thceyn world. Micrometers thick at first, it grows until it strains to hold the world in and the pressure hurts its taut, flattened organs.
Its birthing organ starts spiraling into the world-barrier. It looks like a drill that can unfold into a grappling hook. Having started at one point of the world, where its sire flew up to world-barrier and punctured it so that the Thceynling could gestate in the safety of space, it now digs back through the world-barrier at the antipode. As it makes progress, its body starts loosening from the umbilical pole.
Slowly, the Thceynling drills back through. Its readying body has blotted out the stars and clouded out the sun. Astronomers have folded away their telescopes for the week. When a birth is imminent, all the daytime world knows it from the caustics – dappled sunlight races across the surface of the world, lensed through the ripples of the Thceynling’s heaving body. A giant finger flicks globs of light in through the kitchen windows and across the wide boulevards of the Thceyn world, as if they all live at the bottom of a swimming pool.
At the birthing pole, the hooks come out and brace against the inside of the world. A pause. The Thceynling is moving on pure instinct, and that instinct is saying that it’s safe to let go at the umbilical attachment. It obeys a little, and the world crowns.
The Thceynling convulses in a panic. Its folds are bunched up around the crowning world, and the habitations right underneath are doused in artificial twilight.
Everything is new to the Thceynling, and it is terrified to push more. But it also knows immediately there is no retreat. So with a great shudder that shakes the world, it flexes, three or four times. Its final heave extrudes the rest of the world, and they fall apart from each other. Daylight and starlight rush unobstructed into the Thceyn world.
The Thceynling ripples in space like a plume of fine tissue paper blown out of the world, waves working through its body and tangling it a little in itself. If its hooks loosen now, it will fly away and be lost forever. So will the nutrients it took from the Thceyn world while growing. Everyone hopes this will not happen. It is the means by which the Thceyn world becomes smaller and smaller, and will one day end.
The hooks hold. Hurriedly the Thceynling squirms in through the entrance it has made for itself at the birthing pole, a fabricky mass of flexible muscle and organs. Each part that wiggles inside immediately starts coagulating, folding in on itself with instinctive neatness, matching various organs up to nestle against each other in the correct order. This is a teaching opportunity: doctors bring out their protégées to the roofs and point out the regularities and irregularities.
When it is done, it has eyes, layers of light-catching organs that filter out different frequencies and synthesize their findings into one picture. It can see the world now. It is not so sure about this. Its throat, now fully composed, lets out a bray of dismay.
The Thceynsire has swum out to the ocean under the birthing pole to receive its child. It has spread itself out into a thin, vast sheet, and is making an encouraging bioluminescent display on its welcoming fins. Come! The water is warm, and I will catch you.
The Thceynling squirms uncertainly. The surface of the world is dotted with lights and it has some vague sense of being watched. Some vague sense that any cowardice would be quite public. The briefer its hesitation the better. Besides, it does not like dangling all bunched up here like an overgrown chrysalis. The high-frequency parental lights, which demarcate the boundaries of the catching body in the water, are looking pretty good.
It spreads itself wide to blunt its acceleration, unclenches its hooks, and falls into the world.