Bizarre box-shaped clouds or holes in clouds

This may be some new development. I have never heard of this in 10 years of following the UFO story. (I actually saw a cigar-shaped freighter craft in 1989 in McMinnville, Oregon, together with a client.)

This one was photographed in 1870 over Mt. Washington, New Hampshire, USA, many decades before the US Air Force.

I also do not recall square clouds in Jacques Vallëe’s book about pre-20th century sightings.