Tips for creating NiChannel style forum software implemented in TclHttpd.
Generating captcha images (http://www.captcha.net ) for anti-spam purposes.
Using ImageMagick convert routine, where the captcha code is RKS876:
convert captcha.png -gravity center -pointsize 24 -fill white -annotate 0 'RKS876' -swirl 90 captcha-done.png