What are ‘hole punch clouds’ and where do they come from
A pretty rare phenomenon was seen over Western Washington on Wednesday and several KIRO 7 viewers sent us photos.
Hackaday5y
Punch Those Hole-Drilling Blues Away With A Homebrew Punching Tool
Four times the holes, four times the trouble ... wall of balls to four times the original size, [bitluni] chose to spend a few days building a punch to make the job more appealing.