D800 with AF-S 24-70mm, 1/80 sec at f/6.3, ISO 100, 0EV, 56mm
Even on a cloudy day it's possible to find strong black & white photographic subjects - especially because the sky serves a a great softbox. When you go for a walk and bring you camera, try to look down! An amazing array of interesting subjects and pattern emerges right in front of you.
Here I found an array of stone fragments and leafs that created a interesting pattern - very suitable for a black & white representation. I hope you agree.
The photo was prepared in Lightroom and then converted to B&W in Silver Efex Pro 2.0.