I'm living in Bangalore and I need a big Styrofoam ball for science project!?

I have no idea where 2 find a big stryofoam ball in Banglore, Karnataka, india. I have a project where i hafta make a model of the eye and i decided to cut a styrofoam ball in half and draw in it (thnx 2 all the reasearch i've done, i got this idea) but the only problem is i can't seem 2 find any of those . If u kno where i can get them, pleeeeez tell me.....but if not just give me an alternative for a styrofoam ball in which i can draw the parts of an eye in. thnx 2 all who help...... :)