One auto repair block covers a perimeter of normally e.g. 40x40x40 blocks, which equates to 64'000 blocks. We search for a repairable block each `tick`, which is the in-game-engine timing, normally around 1/50s. In order to find every damaged block we would need to check 64k blocks 50 times per second. Doesn't sound like a good idea if you want to leave some CPU power for other tasks. That is why this mod uses a CPU friendly approach. On every tick we only scan a few random blocks (blocks closer will be scanned more often). The further away a block is, the less the chance the auto repair block will find it. And if you have multiple damaged blocks instead of just one, the random scan will much easier find a block to repair (statistics anybody?). If there is only exactly one damaged block in all of the 64k blocks, don't expect the repair block to find it quickly!