(method (move-piece new-piece next)
          (set! _needs-redraw #t)
          (set! _old-piece _piece)
          (set! _piece new-piece)
          (send _piece set-current-field self)

          (when (eq? (next self) #f) _old-piece)
          (when (not (eq? (next self) #f))
            (send (next self) move-piece _old-piece next)))