Variety of rock piles

Sometimes it seems these things have no single style or purpose - the types just go on and on. Actually I think that is not true but there certainly is a lot of visual variety. Here is a smattering from the last two weekends.

From Leominster.
Big mounds:Little prayer seats:A smeared old pile at a lookout: Split wedged rock:Rock-on-rock group: Ski-jumps: From Boxboro, an old smeared out mound: Ground piles with quartz:Little old things at a spring:Harvard, a remnants of past glory (look in the background):