The terrace walling workshop I taught last weekend involved twelve enthusiastic guys who were eager to discover if a wall could be made using challengingly shaped stones from an old barn foundation.
While there were some nicely squared ones, the four dump loads of stone on the property contained mostly irregular rounded ones (some caked with mortar) and a lot of dirt.
Most of the dressed 'square face' stones had to be laid flat and into the wall (that is, not used upright as 'shiners') to be properly structural, since unlike the barn wall where they came from, there would be no mortar to hold stones together this time.