Dweets awesomed by u/robbyg

function u(t) {

c.width=1920 // clear the canvas
for(i=0;i<9;i++)
x.fillRect(400+i*100+S(t)*300,400,50,200) // draw 50x200 rects

} // 122/140

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    u(t) is called 60 times per second.
    t: Elapsed time in seconds.
    S: Shorthand for Math.sin.
    C: Shorthand for Math.cos.
    T: Shorthand for Math.tan.
    R: Function that generates rgba-strings, usage ex.: R(255, 255, 255, 0.5)
    c: A 1920x1080 canvas.
    x: A 2D context for that canvas.

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robbyg

remix of d/17072 by u/tylertoomey

function u(t) {

for(c.width|=i=0;i<720;i++)x.fillStyle=`hsl(${i/2+t*60},50%,50%)`,k=i/36|0,x.fillRect(9+i%36*53+C(t*9+k)*9,9+k*53+S(t*9+i%36)*9,45,45)

Jan 6 2020 3:09 PM UTC

}// 134/140

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Golfed and then colorized because that's how I start my mornings.

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New_Core

function u(t) {

t?x.drawImage(c,0,a=t*60%6*T+T,T=2e3,T,0,0,T,T):c.height=14e3
x.font="5cm'"
x.fillText("🥱",900+600*S(t*.9),600+350*C(t*2)+a)

Jan 6 2020 9:49 AM UTC

}// 124/140

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old trick..

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tylertoomey

function u(t) {

c.width=1920 // clear the canvas
for(i=0;i<36;i++)
for(k=0;k<20;k++)
x.fillRect(i*53+(C(t*10+k)*10),k*53+(S(t*10+i)*10),50,50)

Jan 5 2020 4:42 AM UTC

}// 126/140

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rodrigo.siqueira

remix of d/17068 by u/pavel

function u(t) {

x.globalAlpha=.08
for(i=8;i--;x.stroke())x.beginPath(r=150*2/3*(i>1)),x.arc(960+t*r*C(a=i+t/5),540+t*t*r*S(a)/25,t*200*(i?1/3:1),0,7)

Jan 5 2020 4:22 AM UTC

}// 133/140

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Turning and folding

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pavel

function u(t) {

for(c.width=640,i=8;i--;x.stroke())x.beginPath(r=150*2/3*(i>1)),x.arc(320+r*C(a=Math.PI/3*i+t),180+r*S(a),150*(i?1/3:1),0,7)

Jan 4 2020 9:07 PM UTC

}// 124/140

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d/17063 #explanation

u/pavel

If you take every point on this picture, turn it into z=x+i*y and feed it through (sqrt(3)+z)/(1+sqrt(3)*z) then decode the resulting complex number as (x', y') and put a point there, you will get d/17063.
u/pavel

Of course you can't take infinitely many points so you will get a pixelated version. To get a proper version you need to solve the equation for the new, mapped, circle given the old circle so that you can use x.arc..

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pavel

function u(t) {

for(c.width=640,i=8;i--;x.stroke())x.beginPath(R=3+12**.5*C(t+=22/21)),j=i<2,x.arc(320+150*(2*!i-j),180+260*S(t)*!j/R,130/(j||R*R)**.5,0,7)

Jan 4 2020 12:23 AM UTC

}// 139/140

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Eight kissing circles

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u/pavel

These are the circles e^is, 1/3*e^is, 1/3*e^is + 2/3*e^i(n*pi/3+t) for n=0..5 transformed via the conformal map (3^.5+z)/(1+3^.5*z)
u/yonatan

Fascinating, but incomprehensible :)
u/yonatan

my best guess: z in the map is coords as a complex number, i is sqrt(-1), e is euler's const? no idea what's s
u/pavel

You got it. s is just a parameter, a real number. If you plot e^is in the complex plane you get a circle (https://en.wikipedia.org/wiki/Euler%27s_form…). Then that map magically moves and resizes things but keeps circles as circles.
u/pavel

This d/17068 is what the circles look like before the mapping. The mapping moves the inner one sideways, outside of the outer circle, and resizes it to be the same size, meanwhile the moving circles keep touching.
u/pavel

Check out https://jsfiddle.net/umL3t1he/9/ on desktop
u/katkip

#apolloniangasket

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robbyg

remix of d/17061 by u/robbyg

function u(t) {

for(c.width|=j=0;j<10;x.fillStyle=R(++j*30))for(i=540;i--;)x.fillRect(Math.acos(C(t+i*.9*j/1000))*520,i*2,i/2.5,2)

Jan 3 2020 7:40 PM UTC

}// 114/140

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u/katkip

fancy

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robbyg

remix of d/17060 by u/daddydomar

function u(t) {

for(c.width|=j=0;j<10;x.fillStyle=R(++j*30))for(i=540;i--;)x.fillRect(Math.acos(S(t+i*j/1000))*600,i*2,6,6)

Jan 3 2020 3:08 PM UTC

}// 107/140

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Golfed a bit and color cause why not?

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daddydomar

function u(t) {

c.width|=0
for(j=0.001;j<0.01;j+=0.001)
{for(i=0;i<530;i++)x.fillRect(Math.acos(S(0.5*t+i*j))*600,i*2,6,6)}

Jan 3 2020 1:08 PM UTC

}// 107/140

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folds

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pavel

function u(t) {

f=n=>n&&C(t*f(n-1))
t?X=(333+X+C(a+=f(9)/15))%333:X=Y=a=98
Y=(180+Y+S(a))%180
for(i=2;i--;x.fillRect(X*6-d*S(a),Y*6+d*C(a),8,8))d=i%2?24:-24

Jan 3 2020 5:16 AM UTC

}// 140/140

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Invisible car

u/andrea270872

nice. could it work to create a zen-garden look?

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