Being flexible can be interpreted in many different ways. As a graduate student and a lead-instructor in a few different collaborative projects, I could offer some thoughts.
The way I see it, a development plan would theoretically cover these three areas.
Physical capital is a development that produces a physical product. This can be a bridge, a road, a building, a computer, or anything that takes a physical form of a product. A society produces a physical capital so that they can use for their benefits.