11.   Rubsamen has also patented a system similar to that found in so-called smart guns.

12.   She named it Rescu-Pal, and patented the system, which uses two transmitter-receivers about the size of a transistor radio.

13.   There may not be an easy way to create more spaces, but Edward Clapper has patented a system for pinpointing the ones that are empty.

14.   Thomas Edison patented a system that allowed an entire concrete home, including stairways and roof, to be cast in less than a day.

15.   Two Japanese inventors have patented a system of generating music with foot, hand, shoulder and elbow movements.

16.   William Fraser, an entrepreneur in Washington, has patented a system for displaying advertising on the conveyor belt that moves groceries toward the cashier.