[JEG in Raleigh (OP)]

First time posting. I am 66 years old, and the attached photo has been a mystery to my family for 59 years.  When I was a child, we lived in Cupertino, California.  We had a large, redwood planter on the edge of our concrete patio.  This planter measured approximately 10' x 10' and was approximately 20" high.  The planter was filled with soil, and we would pull a 1.25" diameter garden hose from a hose bib on the side of the house, over to the planter and water the plants. 

In the attached photo, you can see the hose resting on the surface of the patio on the right, and then bending/sagging up to the left where the hose eventually rested on the 20" tall planter.  This photo was taken on a sunny day.  One would think that the shadow cast by the draped garden hose would be a simple linear shadow of the hose above it.  But as you can see, the shadow that was cast is that of a looped garden hose.  This has always mystified us and we have no explanation for it. It is not a trick or a manipulation of the image.  We ran and got a camera to document this phenomenon when we saw it.   I'm hoping someone can explain why the shadow cast was that of a loop.  Thanks.


SAGGING HOSE PHOTO WITH LOOP SHADOW.png (915.55 kB . 787x590 - viewed 3361 times)

[Hayseed]

Negative(invert) the image and look closely.   Possibilities, right before the pic, the hose was lame and looped.......and wet.  Then the hose was re-positioned, leaving a wet dark print.   And the light is aligned with the hose, showing no shadow at all.  The higher the hose from surface.....the weaker the shadow.

The wet imprint is all we see.  It's apparent or imaginary.

[dlorde]

This can happen when the sun is at the right angle, pretty much overhead or just over the point where the hose leaves the planter. This foreshortens the shadow and emphasises the curve so it appears to be looped.

Here is a kitchen worktop version using an electric cable and a torch:

[sciencepm]

Yes, dlorde got it on point. It’s all about the light setting and perspective in those pictures.

[Hayseed]

Look closely at those shadows.  See the second one, the shadow gets fuzzy on half the loop because of distance from floor.  Look at first picture, the shadow is consistent around all the loop.  Wet spot on floor.