(Or rather, an arrangement triangle; this might not be the only aspect of the process that can be thought about in this kind of structure...)
Some years ago, a friend introduced me to a project management tool he called the Golden Triangle. It framed a project in terms of three dimensions: time, scope and resource. That is, how long you had to complete the project, what you needed to do to complete it, and what resources (human and other) you had available to do it.
The point of the triangle is that you can only ever control two out of the three dimensions. Projects, by definition, are special-occasion enterprises, things you do as one-offs, so each one is new and, whilst it may have routine elements, will overall represent something you’ve not done before. So, you will likely encounter unforeseen obstacles.