An amazing article from Ed Yong describes a new mechanism for pattern formation:
Coloured Cells Chase Each Other To Make A Fish’s Stripes
Zebrafish patterns aren’t just controlled by a chemical reaction-diffusion mechanism — the pigment cells actually chase each other! The different color cells sort themselves into stripes, spots, or other patterns depending on their relative speeds.
R. D. Laing, Knots (1970)
There is something I don’t know
that I am supposed to know.
I don’t know what it is that I don’t know,
and yet am supposed to know,
and I feel I look stupid
if I seem both not to know it
and not to know what it is I don’t know.
Therefore I pretend I know it.
This is nerve-racking
since I don’t know what I must pretend to know.
Therefore I pretend to know everything.
I feel you know what I am supposed to know
but you can’t tell me what it is
because you don’t know that I don’t know what it is.
You may know what I don’t know, but not
that I don’t know it,
and I can’t tell you. So you will have to tell me everything.
R.D. Laing: Wikipedia, Knots, another excerpt of Knots
See also Gregory Bateson’s double bind theory (Wikipedia; article)
Regular and irregular splashing of drops on geometric targets.
Gabriel Juarez, Thomai Gastopoulos, Yibin Zhang, Michael L. Siegel, and Paulo E. Arratia – Phys. Fluids 24, 091105 (2012)
From the Gallery of Fluid Motion, via IAHR Multimedia Library
Image 1: “Scanning electron microscope image of a bryozoan colony” (Source)
Image 2: “This skeleton of a living bryozoan, collected at Bahia de los Angeles, Baja California, clearly shows this typical colonial organiation.
Each individual, or zooid, is enclosed in a sheath of tissue, the zooecium, that in many species secretes a rigid skeleton of calcium carbonate. Each zooid in this electron micrograph is less than a millimeter long and has a single opening, the orifice. Through this opening, the lophophore, a ring of ciliated tentacles centered on the mouth, protrudes to capture small food particles. The lophophore can be retracted very rapidly by specialized retractor muscles, and the opening closed by a doorlike operculum, visible on some of the zooids in the picture at the left.”
Image 3: Membraniporella nitida (source) cc-by-nc-sa
More info: http://en.wikipedia.org/wiki/Bryozoa
“Figure 1: Left panel: Chaotic attractor of a driven anharmonic oscillator on the location-position plane of a stroboscopic map taken with the period of the driving. Right panel: Natural measure on the same chaotic attractor. Lighter colors indicate higher local values of the distribution. Both the attractor and the natural measure are fractal. (From T. Tel, M. Gruiz, Chaotic Dynamics, An Introduction Based on Classical Mechanics, Cambridge University Press, 2006, with permission.)”
Diagram by David H. Terman, Scholarpedia:
Figure 4: Periodic solutions correspond to closed curves in the phase plane.
Diagram by Edward Ott, Scholarpedia:
Figure 1: (a) Double well potential V(x) , and (b) the resulting basins of attraction.