function y=fromsqu_to_cyl(x)
%----------------------------------
% Map from the square [0,1] 
% to the cylinder
%----------------------------------
y=zeros(size(x,1),3);
y(:,1)=cos(2.*pi.*x(:,1));
y(:,2)=sin(2.*pi.*x(:,1));
y(:,3)=1-2.*x(:,2);
end