Also of yellow dots.

From Redundant Coding – Individual Sensitivity Differences

(photo credited by FAA to Armor Tile)

Which is part of a training module on the FAA’s Human Factors Research and Engineering Group website. I’ll cop to it: I didn’t know the FAA had this sort of resource. But this section, at least, is well-written and well-illustrated.

If you’re interested in human factors engineering – and we all are, aren’t we, even if we don’t know it or won’t admit –  it the FAA Human Factors Workbench  is pretty cool. And the more use it gets – the efficiently our tax dollars are used.