Look up "boids". Each critter has a field of view and a current direction. It only responds to what it sees in that field-of-view. If other critters start running, it starts running too. If they stop, it stops. With fish, the minute one turns, there is a flash of light. That instructs all the others to turn as well, providing the flash is bright enough. Maybe it takes two or more.

There was an idea in computing several decades ago about "asynchronous computing". The idea was that you could get rid of the need to have all the different regions of your silicon chip clocked at exactly the same speed. Instead, data would move between different units at different speeds according to demand. If a particular circuit wasn't used, you could put it in a low power state, if something was being filled up with data, you boosted the clock speed. You end up with data "flowing" through the system or data-flow- computing.

So it's much similar to the brain where different regions light up under fMRI analysis as oxygen flow increases as they are used. And scientists have a good idea what different regions of the brain do - usually a high-level function like generate-muscle-motion-to-say-phrase or recognise-name-of-object-from-picture. From other methods of MRI scans, they have identified the pathways where different parts of the brain communicate along, and are able to visualize these as "connectograms", Phineas Gage is the best example.

Then the next challenge is to make a 3D printer that can print out the parts to make a 3D printer, but make sure there's no auto button.

Heart and Lung rhythms are regulated using systems known as reaction-diffusion systems. An entire system is represented by a grid of cells, with every cell is at a particular state with a mix of chemicals, typicall named A,B,C ... There's the reaction part where A->2B, B->B+A, and then there's the diffusion part where the state of each cell is combined with it's neighbors. Each iteration calculates the new state of each cell, and applies the diffusion.

Imagine if you stored your message as particular chemical levels, then ran a few thousand iterations - you would get a new unique state.

But it would seem extremely hard to roll backwards.

Some insect species like those giant hornets actually have random patterns that help identify individuals to each other.. Cows are also able to recognize each other due to the spot patterns - they do exhibit preferences to who they stand beside. My own theory is that snails can recognise each other using the stripy patterns they have on their shells. They would make the perfect bar code that could be read from any direction - a method that was patented in 1949 (http://www.scdigest.com/ontarget/12-12-18-1.php?cid=6548).

Before the discovery of micro-organisms, the belief was that illnesses were caused by bad spirits, objects and places like water-wells being cursed. In fact, there was something bad there - bacteria. Then they had the idea that blood-letting was one way of releasing the "bad spirits" from the body. In a way, it might have worked by reducing bacteria levels in the bloodstream.

Then there were the plague inspectors who wore boots, a long gown, hood and a facemask filled with herbs, spices and perfumes - a primitive version of a white-suit.

Once Newtonian and Maxwellian physics were known, it took researchers 200 years to find applications for those formulae. Batteries, electric circuits, lamps, photo-diodes, speakers, microphones, magnetic tape, magnetic disks, motors, cameras, video camcorders all came from that knowledge.

If a bug lands or even flies past an area of white hair, it becomes immediately noticeable to fast-moving predators like birds.

Every discussion about the best places to work has always brought up the following: the size of homes, property taxes, quality of education, gang crime, homeless levels, commute times as well as political and religious beliefs.

Businesses will also locate to where there are the most qualified workers at the lowest rate.

MP's in Scotland did the same with dentistry. They closed the Edinburgh dental school because in the MP's words "it looked a bit tatty". Over time this led to a shortage of NHS dentists because they all moved into private sector because of the opportunity to earn more money.

I though the Nintendo games (Super Mario 64, Ocarina of Time) started off in parallel steps as you explored each level to find keys and unlock other levels. But eventually after figuring out the optimum sequence of completing levels (get the flying hat first, then get the invisibility hat, get the ten keys, get the skulltulas), then the game becomes linear.

Wouldn't an external USB drive be more practical? You can even make your own by simply buying a $10 case and 2.5" disk drive. Anything up to 500 Gigabytes of storage in your pocket.

You can shift it by +/- 180 degrees. That's good enough for a sinusoidal wave.

Given the magnitude of energy involved (every level on the Richter scale is 10x the one below itI think it would be easier to build floating cities like Buckminster suggested. Build a skyscraper frame using a hollow superstructure, get enough sealed air in the superstructure and you actually end up with a structure that will actually float in the air due to differences in air density.

In London, there are enough taxis in the area, that all you really need to do is raise your arm and hail a cab, when ones passes with a "For Hire" sign.
You couldn't make an app that simpler. Some hotels and conference center receptions have a hotline telephone straight to the taxi cab office.

If the taxi cab dispatch offices brought out there own "app", they could cover every other part of the city.

By that logic, asking a friend or relative if they could give you or someone else a ride would constitute an illegal transaction.

Not so long ago, many Californian toll booths would only cars to travel across for free if there were two or more passengers, and they were actively encouraging ride-sharing to reduce traffic loads.