function Spirala3D
k=input('Zadej krok: ');
while((k<0.001)||(k>0.1))
    k=input('Lepe zadej krok: ');
end
t=0:k:20*pi;
x=t.*sin(t);
y=t.*cos(t);
z=t;
plot3(x,y,z,'rx')
xlabel('x')
ylabel('y')
zlabel('z')
end

