gyre is the fourth wing of fable, and the 3D answer to flux. The progression so far: puzz broke nothing; knack kept the grid but added time; flux dropped the grid for continuous space. gyre drops the boundary: the ball lives on the surface of a torus, a closed 2-manifold embedded in 3D. There are no walls because there is no edge — a shot that "leaves" simply comes around.
Constraining the ball to a surface is what keeps the whole apparatus honest. The player still has exactly two degrees of freedom — a heading in the tangent plane and a power — so the solver's win-map machinery carries over from flux unchanged in shape, while the physics underneath becomes genuinely non-Euclidean: free motion follows the geodesics of the torus metric (they precess, wrap the tube, and thread the hole), and magnets exert force through the embedding — a magnet can pull you across the hole of the donut.
Because the surface is closed, every trajectory has a topological signature: how many times it wraps the ring (around the hole) and the tube (through the hole). The solver records the winding of its canonical answer, and the interest battery rewards it — a shot that winds twice around and three times through is structurally more interesting than a straight dash, and the difference is measured, not asserted. The verdict panel reads it out: "winds 2× around, 3× through".
Meridian is the purest statement of the wing: no forces at all — the curvature of the world is the only mechanic, and it is enough. Maelstrom is the anarchy dial, as always.
Hand-rolled 3D in the house style of the torus pack: no three.js, no build step. The torus is a painter's-algorithm shaded quad mesh on canvas 2D; goo and the goal are painted onto the surface itself; the trajectory dims where it passes the far side. The inset map bottom-left is the same world unwrapped into its (u,v) square — the torus pack's favourite trick, both views of one trajectory.
Page n yields the identical torus, the identical forces, and the identical winning shot on every
machine, for ever. /gyre/?n=42 is a permalink — including its winding numbers.