Geoff Manaugh’s blog post about “ghost streets” (Bldgblog) is fascinating. Cities around the world are filled with streets that are no longer streets. It isn’t too hard to spot the diagonal, no-longer-street “street” in the above photo because of its clear impact to the surrounding buildings.
It seems to me that this phenomenon doesn’t just apply to city streets. The simple act of integrating two (or more) things will inevitably intertwine subsequent design changes. City streets are a form of integration with the unique property of being visible from above. While maybe not as visible, these ghost structures also exist in software systems (and not to be confused with “architecture”).