When talking about software development, often the building construction analogy is used. As every other analogy out there, it is not very accurate. Unfortunately this particular analogy is inaccurate in a very important way. Buildings are the artifacts of the material world, while software is non-material.

The virtual nature of software allows for the transformations impossible in the physical world. In the physical world there might be a possibility to add balconies to the existing house during the expensive renovation, but it is impossible to add a hundred floors to the the two-storey house, just because the grand city architecture plan changed and it is now possible to get bigger return of investment by building a sky-scrapper instead. It is impossible to adjust change the floor plan just before roofing in.