I made these window bars (good use of 5 years of engineering school back in the mid 70’s, no?) from a dowel and a 1×1 years ago when our rat terrier Suzie would get up against the screen of an open window and bark, growl, and flash teeth. One time the mail carrier was delivering a package and she told us she felt threatened by Suzie’s aggressive display, saying it seemed like to dog could go right through the thin bug screen. So I made these bars. Problem fixed.
A memory of Suzie who passed about a month ago. Her bars are still in use.