OBSERVATION 008
海羊歯
Umishida — Feather star
Press the picture or the button to reduce the points.40,000 → 625 → 40 → 1, then back to 40,000.
At fewer points, dots grow and trails linger to help you follow their paths.
“Listen” maps the displayed points to sound.Changing the count rebuilds the sound.
Ten arms undulate in turn.
The pinnules follow them.
If arm and pinnule move together, it becomes an artificial flower.
It is the lag that makes it look alive.
Nor do the ten move together.
Each is offset by a beat, so the wave goes round the arms in order.
While you are watching one place, it has come all the way round.
Read and verify the equation
(i, t,
k = i % 10, j = i / 10 | 0, h = j < 800,
n = j - 800, q = n % 40, e = (n / 40 | 0) % 2 ? 1 : -1, w = (n / 80 | 0) / 40,
a = h ? j / 800 : .12 + .8 * (q / 40),
A = k / 10 * TAU + .38 * sin(a * 3 - t * 2 + k),
r = 26 + 142 * a,
z = 46 * sin(a * 2.1) - 66 * a * a + 8 * sin(t * 2 - a * 4 + k),
x = 200 + r * cos(A), y = 196 + r * sin(A) * .78 - z * 1.05,
L = 34 * sin(PI * a) ** .6 * w * (1 - .3 * w),
c = A + e * (1.15 + .3 * sin(w * 3 - t * 2 + q * .5)),
Q = h ? [x + 1.4 * (j * .618 % 1 - .5), y + 1.4 * (j * .754 % 1 - .5)]
: [x + L * cos(c), y + L * sin(c) * .8],
Dx = 200 + 55 * sin(t + 5.72) + 22 * sin(t * 2 + 3.44),
Dy = 200 + 58 * cos(t + 1.15) + 16 * sin(t * 3 + 5.72)
) => [Dx + (Q[0] - 200) * .68, Dy + (Q[1] - 200) * .68]
Fingerprint of this equation
sha256:822c6066ceb48b3359a13b87166f5d30d1c3304f3ee2008bccb9d29733e10ca6
The same point number and time give the same coordinates.
Trails and the appearance of points depend on rendering settings and the device.
The button above takes the equation out as it is. To count it again yourself:
pbpaste > f.txt && printf %s "$(cat f.txt)" | shasum -a 256
Take it and run it.What appears when you change the equation? Run and rewrite this equation →