McKinsey has been posting a number of classic consulting frameworks under the title "enduring ideas" on the McKinsey Quarterly site. I discussed before: consulting frameworks are great for solving problems, but often less good at communicating solutions.
Recently, the business system was discussed. At McKinsey we used it to analyse the value chain of an industry (manufacturing, sales, distribution, etc.). The basic graphic concept of it (simple arrows) can also be used in another context: communicating a project schedule. See the example below.