Six days ago none of these stones were here. There was a loose pile of stones nearby. Now the wall is done. The setting sun still strikes the distant hill but the wall is in shadow. From this vantage point none of the left over stone are visible and it really looks like the wall is completed.
This picture shows a more honest view of the actual situation. Every stone project always leaves a pile of unused stone. Some of these leftovers are misshapen difficult to use stones that went unchosen for good reason. When they appear at the site of the next project they will likely get passed over again. Eventually the leftover pile contains quite a collection of difficult to use stone. At some point they really need to be dumped over a bank. Perhaps some of them will find a new home tomorrow.
