In reflective Uno, if you use a +2 or +4 card on your opponent, then a +2 or +4 card can be used by your opponent to reflect your card back to you plus their card. If you have another +2 or +4 card, then the game kind of turns into tennis of +2 or +4 cards until one player has no more +2 or +4 cards. Then they have to pick up the sum of all cards used. For example if P1 uses a +2, then P2 uses a +4 & P1 has no more +2 or +4 cards, then they pick up 6 cards.