Round-Robin Pair Scheduler (Tournament & 1-on-1 Rotation)

Lay out N participants around a circle. Fix participant 1 in place. For each round, draw a chord across the diameter — pairs are (1, N), (2, N-1), (3, N-2), and so on. Then rotate everyone except participant 1 clockwise by one position and repeat. After N-1 rounds, every pair has met exactly once. It's the standard construction taught in tournament scheduling and graph theory (decomposition of the complete graph Kn into perfect matchings).

When N is odd, a perfect matching is impossible — someone has to sit out each round. The tool adds a phantom '(Bye)' slot to make the count even, then runs the standard circle method. Across N rounds, every real participant gets exactly one bye. The bye rotates fairly — no one sits out twice while another sits out zero times.

Group Maker splits N people into K disjoint groups in one shot — useful for breakout sessions or team picks. Secret Santa builds a single cyclic gift-giving assignment (A→B→C→A). The round-robin scheduler builds the entire matchup graph over time — N-1 rounds, each round a perfect matching, covering all C(N,2) unordered pairs exactly once. It's the right tool whenever you want a rotation, not a one-shot assignment.

Yes. The randomized order is seeded — the seed is stored in the URL-shareable state, and re-loading the tool reproduces the same layout. If you want fully deterministic output, switch to alphabetical order; same input always yields the same schedule.