Lord Zack's Planescape
Throughout Mechanus exists a series of interlocking cogs that float in space, intersecting at all angles and directions. Many of the cogs are gigantic, stretching many miles across and turn so slowly that the rotation is undetectable. Smaller cogs can move at much higher speeds, but no centripetal force is experienced, except at the very edges. Usually smaller cogs bunch up with larger ones; these are called knots. The gravitational force is oriented towards the face of each individual cog, making intercog travel a disconcerting experience for the uninitiated.