function xdot=spiralsource(t,x)
% Example: Spiral-Source

xdot(1)=x(1)+2.*x(2);
xdot(2)=-2.*x(1)+x(2);
xdot=xdot';



% "Complex and Chaotic Nonlinear Dynamics. 
% Advances in Economics and Finance, 
% Mathematics and Statistics" 
% T.Vialar, Springer 2009
% Copyright(c).