ABSTRACT
In what ways can an arrangement of coins be reconfigured by a sequence of moves where each move slides one coin and places it next to at least two other coins? Martin Gardner publicized this family of sliding-coin puzzles (among others) in 1966. Recently, a general form of such puzzles was solved both mathematically and algorithmically. We describe the known results on this problem, and show several examples in honor of Martin Gardner for the Fifth Gathering for Gardner.
