A method and apparatus for filtering an air stream with an aqueous froth are provided. The game system allows the player to feel as if the three-dimensional game space is tilted in accordance with a tilt of a game device, etc. The elastomer element has a bulge to the inside. One of the tension members can be a strap member, and the other tension member can be a sheet member. The container also may have upwardly extending fingers in the removable tray for securing a material.