I don't see how you can use any terms other than vertical (upright) and horizontal. I don't have a card in front of me, but I don't think there's any standard feature which distinguished two positions 180 degrees apart. " My understanding is that instructions are given with respect to the player who is playing the card at the time.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.