The present invention relates to a module for a modular pressure distribution system comprising a plurality of modules. The exercise apparatus is an adaptation of the exercise ball or Swiss ball. The substantially cylindrical member is provided with a fluid inlet for receiving a pressurized fluid and an expandable bladder located within the substantially cylindrical member in fluid communication with the fluid inlet, wherein the bladder is sized and positioned such that when expanded, it blocks the drain to the passage of water. The latter comprises intelligent agents for establishing two-way data exchange sessions, thereby allowing the smart card to have a \u201cweb\u201d server functionality. The candle is arranged during operation to sustain propagation of a plurality of burn fronts therethrough, the fronts propagating in different directions.