Linked Decks

Two separate decks of cards. On the back of the cards is a closed eye, surrounded by a red or blue pattern (depending on the deck).

When a black card is removed from a deck, or on top, the eye on the white version of that card slightly opens. You can then open the eye with an activation word, at which the eye on the corresponding black card opens as well. You can look through this eye as if using enter image.

The owner can peer through any red card at will. Drawing a random card and peering through it is a standard action, while going through the deck and selecting a specific card is a full-round action. If the corresponding blue card is still shuffled in with the rest of the blue deck, it is automatically moved to the top of that deck, ready to be drawn by whoever uses it.