These have been on a wall at my office for a long time, originally my Father obtained the first one in the winter of 60/61 from Jim Warne, Engineers Testing Laboratory, Phoenix.
I too like particularly the 3rd one, maybe because too many a times it still happens unfortunately, even though at lower altitudes. Does the copyright still holds?
The first one is reminiscent of a story (probably true alas) about a structural engineer seriously testing the soil by the heel of his shoe. he was male, so my spontaneuos thought is that he might have reached a deeper depth by using more adequate tools: