I took a series of pictures while my husband graciously posed for me. I had this idea for awhile but I needed the following conditions: A sunny day (for shadow); Mid day sun (otherwise the shadow would be too elongated for my purposes), Husband available (to pose shadow on cart).
I manipulated the photo, adjusting the contrast, shadows and highlights to make the creeper more noticeable. Below are some additional poses not manipulated in a photo program.
Mechanics lay on creepers to facing up to roll under cars when they are working on them. Most larger shops now have a hoist to lift cars up high enough that you can stand while working on them.