The last thing J Allan Hynek showed me what he was working on was a compendium of different types of UFO shapes. There were over 30 types but the one type that has been recorded since his death that did not appear in his collection is the dynamic type that separated into many like images from three to many and form patterns or shapes.

Over the last 60 years there is a progressive change in the shape and navigation abilities. Some earlier types do not appear anymore.