"So natralists observe, a flea
Hath smaller fleas that on him prey,
And these have smaller fleas that bite 'em,
And so proceed ad infinitum." Jonathan Swift

"Great fleas have little fleas upon their backs to bite 'em,
And little fleas have lesser fleas, and so ad infinitum.
And the great fleas themselves, in turn, have greater fleas to go on,
While these again have greater still, and greater still, and so on." Augustus De Morgan


An infinite dissection of the plane by logarithmic spirals.

There is a nice bistable perception in the animation: when I first see it, I percieve a wholistic pattern rotating clockwise and shrinking. But after a short time, I see half the contours as fixed, and the other half rotating (with no shrinking). Try fixating on a single edge point to experience the second percept.

The pattern is the basis of Orthologia trispiralis, and the pattern and transform is the basis for the animation Orthologia twist.

Here's the geeky description. It's a checkerboard division (8x2) of the plane by logarithmic spirals with a pitch of +/- pi/4 radians. The checkerboard is colored (orthogonal to the contours) by the first 2^3 = 8 elements of the Thue-Morse sequence, [0 1 1 0 1 0 0 1]. The relative phase between the two sets of opposite chirality spirals rotates through pi/2 radians; in this example the phase of one set is fixed.

MATLAB

[Broken link: A volume rendering derived from the animation, with the time axis transposed to a third spatial dimension.]


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