Using pinch gestures to navigate user interface layers of an application. Unlike a compact disc, the CD ColorDisc does not store digital information. The latching mechanism assembly is adapted to containing the structural element in a non-deployed state until it is remotely activated or de-latched. The opening is of a predetermined size sufficient to receive a fan. The system also has an optical shield configured for shielding said image acquisition unit from receiving undesired electromagnetic radiation from at least one direction different from said desired direction. The target body is configured as a spreader aligned coaxial with the liquid stream and expanding in the direction of flow up to a spill-over rim, which can be especially conical.