Three of Hearts
Teams are shown a card trick where the 3 of hearts is forced, and then an illusion where the entire deck is the 3 of hearts. They are then given the puzzle deck, which consists almost entirely of 3 of hearts. Sample cards:
The cards also have eight different backs. Some sample backs:
Finally, there are two clue cards. Both sides of both cards are the same:
The first observation is that there are eight different card backs. When sorted into these groups, the enumerations of the backs are 4/4/6/6/7/7/8/10 (this sums to 52 cards). Observant teams may note that these counts are similar to the counts on the clue cards, but one greater.
The next thing that can be focused on is the clues themselves or the card fronts. The hook for the clues is that they all refer to popular card games:
|Instruction to an angler||GO FISH|
|Gem set by itself||SOLITAIRE|
|Confrontation between nations||WAR|
Observant teams will note that these clues are in alphabetical order. Teams can discern the encoding of the cards by trial and error, or by focusing on the smaller sets and trying to extract GIN or WAR from them. The encoding is ternary, where a hollow heart is a 0, a filled heart is a 1, and two filled hearts is a 2. The cards are not rotationally symmetric- the 3s in the corners and all of the hearts are the same way up. So this set of cards can be decoded thusly:
Which matches the "Confrontation between nations" clue, with one leftover letter (L). Reading all the leftover letters (one per clue), in clue order (which is alphabetical by answer), you receive the answer FREECELL, another card game.