Here are two bona-fide job interview questions, as reported by two frazzled interviewees. They sure could have used some help from the Lafayette Problem Group. [Microsoft] Your boss wants you to design a calendar that she will place on her desk right next to the promotion forms. She gives you two plain wooden cubes that will fit side-by-side in a wooden holder like so (front view): _____ _____ _ | || | _ |X||cube1||cube2||X| |X||_____||_____||X| |X|--------------|X| |XXXwoodenholderXXX| ------------------ Your job is to place a single digit between 0 and 9 on each of the twelve faces of the cubes so that any day of any month can be displayed. Can you do it? [D. E. Shaw, a financial firm in NYC] You and a friend are trying to perform the following "magic" trick. Your friend leaves the room. You hand a standard deck of 52 cards to someone in the audience. The audience member chooses any five cards from the deck and hands those five cards to you. Now, you must select one of these cards to keep concealed from your friend, and you must display the other four cards side-by-side on a table just like so: ___ ___ ___ ___ | | | | | | | | | | | | | | | | |___| |___| |___| |___| Your friend now enters the room, examines the only the four displayed cards, and then tells the audience what's on the concealed card. (Whoa -- what a neat trick!) Can you and your friend come up with a scheme so that, based solely on the four displayed cards, the fifth card can always be determined?