There are 52 cards in a standard deck of playing cards: four suits of 13 cards each. To design a deck of cards, one needs to establish the four suits, each with its own symbol and/or concept, and find a logic for generating the 13 cards in each suit, usually related to the numbers from 1 to 13. My exchange gift is a booklet summarizing my progress to date in designing a set of playing cards based on ideas that Martin Gardner wrote about in his books and columns. The talk corresponding to this item can be found here:
https://www.youtube.com/watch?v=ZijlID83FTg&t=15s