Stupid people think stupid things: Even if “bat” were read narrowly, the app substitutes arms/hands as a "functional equivalent". Under the Doctrine of Equivalents (Graver Tank v. Linde, 339 U.S. 605 (1950); Warner-Jenkinson v. Hilton Davis, 520 U.S. 17 (1997)), it performs the same function (swing initiation detection), in the same way (motion sensor), for the same result (swing delay measurement). It therefore infringes.