"All war is deception", this according to Sun Tzu's The Art of War. An inventor from Indiana, Anthony Dewayne Johnson, recently published a patent application that takes this teaching to heart,  US20190033781A1 Special holographic security systems and similar holographic defense systems. Saving lives and improving the effectiveness of home, commercial and military security systems is the primary goal of Johnson's 2019 application.

The home and commercial applications are designed to augment existing security systems. In addition to monitoring an area and communicating with law enforcement, the holographic security system provides visual and audio warnings. Pre-programmed images and sounds can be presented to frighten intruders, such as the resident, a security guard or a barking dog. In addition, the representations can be linked to remote devices, like  a smartphone, and provide real-time communication with the threat, i.e., "I've called the police" or "Do you feel lucky? Well, do you, punk?"

US20150013737 A1 Portable Personal Seating Barrier
Inventor: Daly, Lisa Margaret
Filed: 2014-01-31 Published: 2015-01-15

Problem: Public spaces and public transportation can be too crowded and encroach on a person's personal space.

Solution:  A barrier which defines a space for the user and restricts sensory feedback (e.g., visual, touch, and/or auditory feedback) from others.

The application includes an embodiment for the use of "antibacterial, antimicrobial, antifungal" materials separating the user from others. A much needed feature as the application points out regarding public transportation,

"One seated passenger may eat, engage in personal grooming, cough, sneeze, physically rub against, stare, and otherwise provide unwanted stimuli to the person beside whom they are seated. There have even been cases of passengers urinating on bench seats with the urine running onto the seat and person seated next to them and of passengers vomiting and bleeding on passengers seated beside them."