• ✓One engine for three sports — what differs is the feel in the hand, not three copies of the code
• ✓The physics is pure, and verify:rally plays 90 seconds of each sport: if a perfect player at a finger's speed concedes even one point, the ball is faster than a hand and the test fails
• ✓It fails the other way too: a poor player who concedes nothing means there is nothing at stake
• ✓Two fingers at once, one bat each: pointers are keyed per SIDE, never one shared reference (the camp-swap lesson)
• ✓The handicap is agreed out loud before the first serve — small, normal or big bat per end — instead of the game quietly helping somebody
• ✓Four points down in a row offers that end a breath — and a bigger bat, with the screen saying plainly that it is not cheating
• ✓The result card leads with the longest rally the two of them built together; the points sit under it, and the word for losing is not on it
• ✓Still a code-drawn court: no painted table, bats or ball yetplanned
• ✓One device only so far — no cross-device match over the networkplanned

✓ = done · ☐ = planned. Every game is built one step at a time like this.