One phone opens a room and sends the code. Both batters get the same nine at-bats at the same time, each with their own diamond and their own three outs. Thirty seconds a swing — no swing is an out.

Three outs or nine at-bats ends your side. Most runs wins. If your rival is done and you pass them, that's a walk-off. A tie goes to sudden death: one shared at-bat at a time, the bigger hit wins.

Rooms last a day. A phone that goes quiet keeps taking outs on the clock — come back by the link to keep batting. Rematch swaps home and away.