[quote author=Fu-Kwun Hwang link=topic=13.msg10530#msg10530 date=1405910619]
I have modified the above simulation and make a new one.
Please click
to view the new version.
I hope it is what you want. (You need to click the - checkbox to make the particle being pulled down.
All the particles will have ghost particles a few times steps backward or forward (you need to change dt2 to see the difference)

thanks for the simulation.