A ring station spins to fake gravity. Drop a ball from head height: outside, it flies straight; inside the ring it seems to curve. Same ring numbers as the 3D explorer (radius about 100 m, 2.3 rpm).
The science
Spin gravity. A floor at radius r rotating at omega pushes on you with the centripetal acceleration g = omega^2 r; rpm = 30 omega/pi.
Gradient. Head at height h above the floor feels omega^2 (r - h), a fraction h/r less. On a 100 m ring that is 2 % for a 2 m person.
Coriolis. In the rotating frame a body moving with velocity v feels a = -2 omega x v - omega x (omega x r). Walking at v along the spin gives 2 omega v sideways; a dropped ball lands displaced against the spin direction.
Orbit. T = 2 pi sqrt(a^3/mu) with mu = 3.986e14 m3/s2; the shadow fraction of a circular orbit is asin(R_E/a)/pi (cylindrical shadow, sun in orbit plane).
Honest limits. A rigid ring in flat space: no structural flex, no air drag on the ball, no tidal terms of the orbit, and the spin rate is held constant. The numbers are classroom values for an illustrative station, not a design. The ball is a point mass.