For the uninitiated, this is a representation of the Survivorship Bias.

Essentially, the red dots represent bullet holes from aircraft which returned from battle.

If you were to ask someone which places should be reinforced with armour, someone who has the Survivorship Bias would say "where the red dots are", whereas people who know anything about engineering would say "everywhere else!"

It's like saying: "why are you wearing a helmet? I've met hundreds of soldiers and none of them have ever been shot in the head, helmets are a waste of good armour."

A true fact: Did you know wearing a helmet increases your chances of dying of cancer.