A container for receiving an electric device in a recess. A game controller in communication over an access network with a push-to-talkpush-to-video server, and plurality of push-to-talkpush-to-video clients implements group games in the PTTPTV based communication network. An annular thinnest wall portion 4a is formed in the wall of the body 4 so that the thinnest wall portion 4a is the first to come in contact with the body molding planes 14 of a split mold 13. The mixture is then heated to a temperature not lower than the dissolving point thereby forming a sol.