In the card game DOS, the sequel to UNO, there is a rule stating:
DOS RULE: If you ever have EXACTLY TWO CARDS in your hand, you must shout out "DOS!" (meaning "two"). If you forget to do so and another player calls out "DOS!" before you do, you must immediately draw two cards as a penalty.If this happens during your turn, do not add the penalty cards to your hand until the end of your turn.
If there is a six on one stack and I have three cards in my hand, then decide to play a two and a four but play both cards simultaneously (on top of each other), am I at risk of being penalised for not saying "DOS!"? On one side, I never had 2 cards in my hand, I went straight from 3 cards to one, but on the other hand, there must have been a time at which I had played one card and not the other, therefore I can be called for it.