Free to filter software for windows

Filthy Filter is a interesting tool that passes sound through a filter varying over time, based on a grayscale image created by the user.
Filthy Filter has an interpretation as follows: the vertical dimension corresponds to time (time passes downwards), and the horizontal - to frequency.
If the picture is cut into thin horizontal stripes, each such stripe will represent the filter frequency response at a specific instant of time.
The low frequencies (pitches) are on the left side of the stripe and the high ones - on the right. Bright pieces denote allowing signal to pass through the filter and dark pieces denote attenuation.
This explanation was probably not really clear, so Ill try to show it on examples.

Mail Filter was developed to be an email filter application. It requires you have your own domain, that you are using qmail for mail handling (although it might be possible to adapt it for others since it is just scripts) and that your domain host is the helpful type since it needs a entry in each email accounts .qmail file.