This is my first filter. I played around with the photoshop sdk and needed a simple fast to implement effect. So i used this old demo effect which uses soem simple sinus calculations to generate nice patterns like this one:

Download Sinedots here (35kb, requires win32 and a photoshop host v3.0+).
There is no Mac version! Probably there will never be one. Sorry.
(last updated on 31th of Juli, 1999)