The essence of a Turing system is that you have two components, both of which can spread through space (or at least behave as if they do). These could be anything from the ripples of sand on a dune to two chemicals moving through the sticky goop holding cells together in a developing embryo. The key thing is that whatever they are, the two things spread at different speeds, one faster than the other.
One component is to be auto-activating, meaning that it can turn on the machinery that makes more of itself. But this activator also produces the second component – an inhibitor that switches off the activator. Crucially, the inhibitor has to move at a faster pace than the activator through space.
The beauty of it is that Turing systems are completely self-contained, self-starting and self-organising. According to Green, all that one needs to get going is just a little bit of activator. The first thing it does is make more of itself. And what prevents it from ramping up forever? As soon as it gets to a certain level it switches on the inhibitor, which builds up to stop it.
“The way to think about it is that as the activator builds up it has a head start,” says Green. “So you end up with, say, a black stripe, but the inhibitor then builds up and spreads more quickly. At a certain point it catches up with the activator in space and stops it in its tracks. And that makes one stripe.”
From these simple components you can create a world of patterns. The fearsome equations are just a way of describing those two things. All you need to do is adjust the conditions, or ‘parameters’. Tweaking the rates of spreading and decay, or changing how good the activator is at turning itself on and how quickly the inhibitor shuts it down, subtly alters the pattern to create spots or stripes, swirls or splodges.
- More Here
One component is to be auto-activating, meaning that it can turn on the machinery that makes more of itself. But this activator also produces the second component – an inhibitor that switches off the activator. Crucially, the inhibitor has to move at a faster pace than the activator through space.
The beauty of it is that Turing systems are completely self-contained, self-starting and self-organising. According to Green, all that one needs to get going is just a little bit of activator. The first thing it does is make more of itself. And what prevents it from ramping up forever? As soon as it gets to a certain level it switches on the inhibitor, which builds up to stop it.
“The way to think about it is that as the activator builds up it has a head start,” says Green. “So you end up with, say, a black stripe, but the inhibitor then builds up and spreads more quickly. At a certain point it catches up with the activator in space and stops it in its tracks. And that makes one stripe.”
From these simple components you can create a world of patterns. The fearsome equations are just a way of describing those two things. All you need to do is adjust the conditions, or ‘parameters’. Tweaking the rates of spreading and decay, or changing how good the activator is at turning itself on and how quickly the inhibitor shuts it down, subtly alters the pattern to create spots or stripes, swirls or splodges.
- More Here
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