A breast prosthesis for wearing against a chest of a user includes a bag, a first silicone rubber and a silicone agglomerate putty. Alternatively, the fish-shaped body may be provided with a bill and a lifting tab spaced apart from the bill. The power supply circuit is configured for powering the heat dissipation device. Also disclosed is at least one embodiment of a procedure for controlling a hybrid drive system to achieve the optimum energy recovery. Additional user commands that specify characters to delete from the current set of characters and characters to add to the current set of characters are received. The invention also provides a method of operating a water feature comprising at least one vessel containing a volume of water, comprising the steps of causing the or a volume of water to rotate about an axis thereof so as to form a vortex therein and causing the rotating volume of water to vary in height over time.