Kinetic Trajectory Test

I spotted a pristine glass marble trapped directly in the recessed mortar seam between two patio flagstones—obviously an uncataloged spherical hazard! After verifying zero incoming foot traffic, I dropped onto my knees, hooked both curved hands around the smooth sphere, and administered a five-millimeter test push. It didn't jam! In fact, the gentle downward grade sent it gliding down the stone channel with practically zero surface friction until it bumped softly into a mossy paver edge. Pure Newtonian mechanics! I scurried right behind it, retrieving and rolling it three separate times to benchmark deceleration rates. Technically a friction assessment, obviously, but honestly... remarkably fun.