[PTTG]

Toroidal-1 is an especially weird one.

Since prehistory, this no-mana Earth has had a standing spacetime distortion field which connects an area 1,600 km wide with its antipode. Specifically, a vessel can sail south from Madagascar to ultimately end up sailing north into Vancouver. Or, it can sail west from Umpqua territory (present-day Oregon), and arrive in South Africa.

Either route is fraught, but not impassible.

History remained mostly consistent until around 500CE, at which point sailors established regular trade between sub-Saharan Africa and the Pacific Northwest. The distribution of food crops from and to Turtle Island (and the slow introduction of Old World diseases) lead to cultural alliances never seen in our history.

Toroidal-2 is an outright donut-shaped band of rock; its surface environment is earthlike, with a band of polar climes around the inner face, desert bands on the "top" and "bottom" of the donut, and a tropical band around the outer belt. It spins along a long axis, giving each part at least a little while of sunlight.

It appears to have been populated for the past 7000 years, with the occasional peoplefall from echoes. It's currently a mid-TL6 with wide margins; the population density is quite low.

Incidentally, the part of the planet that is correlated with Infinity Inc's headquarters has a huge rock formation that, when seen from the right angle, resembles a rude gesture.