Corrugated plastic cutter. 2:05 video.
https://www.youtube.com/watch?v=TmI6oqexalw
Previously:
https://www.homemadetools.net/forum/...009#post160550
https://www.homemadetools.net/forum/...591#post162773
https://www.homemadetools.net/forum/...859#post148514
https://www.homemadetools.net/forum/...090#post149542
https://www.homemadetools.net/forum/...277#post138673