The other night I was mountain biking in Rothrock State Forest and encountered three porcupines. This one was along the fire road that parallels the Mid-State Trail near its intersection with Greenwood Spur.
As I approached by bike, he turned his back to me and ruffled his needles. He hid behind this rock where he tucked his head underneath, probably for defense. I snapped the photo when he peaked to see if I was still there.