The simplest and easiest way to do this would be one simple rule: If no one is on base, the batter cannot step out of the batters box, and the pitch must be delivered within 15 seconds. I came up with the idea of a pitch clock last homestand. It starts when the umpire signals the ball "in play". He will call this as soon as the pitcher gets the ball, or while the catcher has it and isn't getting it back quickly. This stops the defense from delaying the game. It counts down starting from 25. The pitcher can start his delivery any time after it reaches 20. The pitch is valid whether the batter is in the box or not, but he is still out if he hits it while out of the box. If the timer reaches 0, the ump calls a ball and immediately restarts the clock. It would change the pace of the batter/pitcher match up, but quickly speed up the overall game.