I am often amazed when walking in a city at the art I find beneath my feet in the form of grates, tree rings, manhole covers, and various other covers and openings.
Just another fun photoshop project. The challenge is in adjusting the image but keeping the realism. Skewing, scaling, selective replacement and layering all should work together to create an image that is believable. This one combines several images and each image brings something to the final but is not entirely there.