The law also states that 'the referee decides when a penalty kick is complete'.
Where a penalty kick is taken during normal play and the ball rebounds (from goalposts and/or crossbar and/or goalkeeper) and remains on the field of play, then play continues. The kicker taking the penalty kick may not touch the ball again until it has been touched by another player. If the kicker does touch the ball again before another player then an indirect free kick would be awarded unless it was 'hand ball' in which case a direct free kick would be awarded to the defending team.