If a unit wins the combat and its formation already extends to the enemy's flanks, then models may be moved from the rear ranks round the sides of the enemy unit. These extra models are described as lapping round. You may move up to two models around each flank, assuming that there is room and that the flank is not blocked by another unit, buildings, or terrain. Once models have covered the enemy's flanks, further models may be lapped around the rear should they win a further turn. In this way it is possible to extend your line and surround an enemy unit completely.