A folding chair includes a lower assembly including a lower block and three or more legs pivotally connected to the lower block; an upper assembly including an upper block and three or more arms pivotally connected to the upper block; a middle assembly connecting the upper assembly and the lower assembly; and a flexible seat including the same number of end portions as the number of the arms, wherein each end portion is arranged at an end of each arm away from the upper block, wherein the upper block is provided with a stop portion to limit the rotation angle of the arms, and wherein the arms are retractable, the flexible seat is arranged to be in a relaxed state when the arms are in a retracted state, and in a tight state when the arms are in an extended state.

A seat occupancy indicator device and method; the seat occupancy indicator device includes a housing made of a rigid material (the housing has a housing-exterior and a housing-interior-volume); a plurality of indicator lights, the plurality of indicator lights disposed on the housing-exterior, the plurality of indicator lights viewable from a location outside of the housing; a control-circuit, the control-circuit located within the housing-interior-volume, the control-circuit communicatively coupled to the plurality of indicator lights. The seat occupancy indicator is useful for indicating occupancy of a seat.

A seat occupancy indicator device and method; the seat occupancy indicator device includes a housing made of a rigid material (the housing has a housing-exterior and a housing-interior-volume); a plurality of indicator lights, the plurality of indicator lights disposed on the housing-exterior, the plurality of indicator lights viewable from a location outside of the housing; a control-circuit, the control-circuit located within the housing-interior-volume, the control-circuit communicatively coupled to the plurality of indicator lights. The seat occupancy indicator is useful for indicating occupancy of a seat.

A foldable chair, including a first bracket and a second bracket that are hingedly fixed in an X-shape, and an adjusting mechanism connecting an upper portion of the first bracket and a lower portion of the second bracket. The adjusting mechanism includes a fixing member and a movable member, the fixing member including a slide groove, and the movable member including a limit member movable within the slide groove; the slide groove has a serrated first inner side wall and a smooth second inner side wall, and the limit member is snapable to the first inner side wall.

A foldable chair, including a first bracket and a second bracket that are hingedly fixed in an X-shape, and an adjusting mechanism connecting an upper portion of the first bracket and a lower portion of the second bracket. The adjusting mechanism includes a fixing member and a movable member, the fixing member including a slide groove, and the movable member including a limit member movable within the slide groove; the slide groove has a serrated first inner side wall and a smooth second inner side wall, and the limit member is snapable to the first inner side wall.