z = [0:0.05:5];
plot3 (cos (2*pi*z), sin (2*pi*z), z, ";helix;");
plot3 (z, exp (2i*pi*z), ";complex sinusoid;");

hold on
for x = ugx:0.01:ogx
 for y = ugy:0.01:ogy
  for z = ugz:0.01:ogz
   eps = 0.1; % oder so
   if (abs(lala) < eps) 
    plot3(x,y,z,'*')
   end
  end
 end
end

tic
a = zeros(1000,3);
az = 0;
delta = 0.1;
eps = 0.1;
for x = -2:delta:2
 for y = -2:delta:2
  for z = 0:delta:4
   erg1 = (x-1)^2+y^2-4; % N_2
   erg2 = x^2+y^2; % A
   if abs(erg1-z)<eps
    if erg2<=4
     az = az + 1;
     a(az,1) = x;
     a(az,2) = y;
     a(az,3) = z;
    end
   end
  end
 end
end
az
toc
hold on
for i = 1:az
 plot3(a(i,1),a(i,2),a(i,3),'.');
end
view(45,45)
toc

clf
a = [1;0];
 
f = @(x,y) sqrt((x-a(1)).^2 + (y-a(2)).^2);
 
I_A = @(x,y) ((x.^2+y.^2)<=4);
V = [0 1 2 3];
 
h = 0.1;
y = -4:h:4;
x = -2:h:6;
[X,Y] = meshgrid(x,y);
 
h2 = figure(2)
hold on
surf(X,Y,f(X,Y), 'FaceAlpha', 0.5)
contour(X,Y,f(X,Y), V)
view(32,35)
grid
hold off
colormap(h2, parula)
shading interp
colorbar