Drywall mud box taping tool.
https://www.youtube.com/watch?v=D2UOkbXc01A
Previously:
https://www.homemadetools.net/forum/...190#post153824
https://www.homemadetools.net/forum/...206#post145873
https://www.homemadetools.net/forum/...728#post155816
https://www.homemadetools.net/forum/...410#post158389
