Back in the 1800's archaeologists surveyed the ancient sites at Hampi and tried to piece together what they had orignally looked like.

At this time, many of the original structures had become dismantled and the stones each building had been built from were scattered all around the site.
These pictures show how archaeologists pieced together the original design and numbered many of the stones during this process. It also looks like they did this for buildings that were partially complete, but which needed to be dismantled to make them safe or restore missing sections.

There's a nice symmetry in this story. One of the major places of interest here is the Kings Royal baths (see final picture). It turns out that the original builders must have worked from a detailed plan as there's evidence that the original stonemasons marked each stone here with an identifier, presumably to help during the construction!