function EllipticTheta[1,z,0.1*Exp[i*pi*1/10] in the complex plane.
Jan Homann
made with Mathematica, own work. See <a href="//commons.wikimedia.org/wiki/User:Jan_Homann/Mathematics" title="User:Jan Homann/Mathematics">User:Jan_Homann/Mathematics</a> for an explanation of how to generate images like these with Mathematica.