At a party for our perfectly logical philosophy friends Sheila and Colin, a surprise has been hidden under one of these colored tiles: Each friend is privately told a piece of information about where the surprise is. Sheila knows the shape of the tile. Colin knows the color of the tile.
Host: Do either of you know where the surprise is? . . . Awkward long silence. . . Host: Do you know now? . . . More awkward silence. . . Sheila, Colin: (simultaneously): Now I know where it is! Question. Where is the surprise?
