Animation
Spiral Animation
MATLAB code for above video. The colors are different from the video but animation is same. In for loop the value of n increments by 1 this gives a phase difference to function cos(r-0.04*n*pi) and gives a rotation in spiral. Variable k decides the number of streaks coming out of the center of image. For k = 1 one black and one white streak will come out. Some variations in the animation can be made by using these functions.
zval=(sin(5*(r)+k*tt-0.11*pi*n));
zval=(sin(-2.5*log(r)+k*tt+0.1*pi*n));
zval=(sin(10*r.^2+k*tt-0.11*pi*n));
total=150;
lim=2*pi;
k=1;
x = linspace(-lim,lim,total);
y = linspace(-lim,lim,total);
c = zeros(length(y),length(x));
lenx = length(x);
leny = length(y);
for n = 1:lenx
c(n,:) = x(n)+i*y(:);
end
zval = zeros(lenx,leny);
tt=angle(c);
r=abs(c);
colormap gray(128)
for n=1:150
zval=(sin(6*cos(r-0.04*n*pi)+k*tt));
pcolor(zval)
shading interp
axis square off
drawnow
end