Twister is a program made by Penguinboy that generates a displacement that would usually take an extremely long time, or just be impossible to do in Hammer.
Twister started out as a program with the single purpose of generating a displacement that twisted 90 degrees along the central axis, to give the result of a lookalike of the twisted corridor from 'The Legend of Zelda: Ocarina of Time'.
KNOWN BUGS:
Using the save button in the 3D preview will ignore the length override setting in curve and corner modes. If you want to override length, use the "Go!" button on the main form.
Archived page and alternative download:
https://web.archive.org/web/20200224013338/http://www.users.on.net/~imperialcarp/Twister/Twister.html