No, you cannot stack colors in Uno.
No, you cannot stack numbers in Uno.
No, in Uno, you are not allowed to stack cards.
No, you cannot stack reverse cards in Uno.
No, in Uno Flip, you cannot stack cards or add 5 to the stack.
No, in Uno, you cannot stack cards of the same number.
No, in Uno, you cannot stack draw 4 cards.
No, in Uno you can only stack two cards at a time.
No, in Uno you cannot stack the same number on top of each other.
No, you cannot stack a Draw 4 on a Draw 2 in Uno.
Yes, in Uno, you can stack cards to change the direction of play.
In Uno, you can stack cards of the same number but different colors to add to the penalty for the next player. This is allowed as long as the player has the same number card in their hand and it is their turn.
No, you cannot stack a 2 card on top of a 4 card in the game of Uno.