Some sets of activities are cyclical: one event follows another in a regular pattern.
The most valuable cycle model we have used is the Learning Cycle model designed by Peter Honey and Alan Mumford. This builds on work by David Kolb to identify the different types of activity that people need to undertake in order to develop skills, and is a particularly useful framework to support experiential and work-based learning.

The value of most cycle models is that they identify different activities or functions that make up the whole, and that they have a continuing dynamic. In the Learning Cycle, the first round of Action-Reflection-Knowledge-Planning naturally leads into a second round, and so on into a third.
Peter Honey and Alan Mumford 1988 The Manual of Learning Styles Peter Honey, Maidenhead