California 2050

Inside the BART train tunnels, LED screens shoot video advertisements that keep pace with the speed of the trains.

Rockets and fireworks flash past the car during intermissions, provoking screams and laughter from the younger riders.

Sometimes the holographic images in key sections of tunnel jump out and seem to fill the space in front of you, hover next to you as a cartoon character or a spokesperson, or they bathe you in an avatar skin.

Spokesmodels, operating on focused frequencies cued to the individual inner ear, smile and hawk products customized to you via facial recognition software.

Cancellation headphones could rid you of this annoyance. Some early adopting tech-heads wear holographic face shields that projected down from a visor, foiling the attempts of cameras to read their face.

Hacking the tunnel LEDs allowed a new form of graffiti, with a spray can made of pixels.

Sometimes birthday or wedding announcements flashed across the screen. Hubby could remember your anniversary remotely, requesting that an individualized sentiment be broadcast to you on your morning commute.

The Luddites among us just don their headphones and close their eyes, dreaming of simpler times.