Iteration repeats the design process to improve a concept. The first version is never the best. It is a starting point. The designer builds a rough version, tests it, learns what works, and revises. Each cycle refines the design. The process continues until the design meets the goals or the deadline arrives. Iteration is how good designs become great. It is also how bad designs get caught early. A prototype tested in a day saves weeks of development on the wrong path.

The concept comes from software development. Agile methodologies emphasize short cycles of build, test, and learn. Design borrowed the approach because it fits. Design problems are complex. The right answer is not obvious. It emerges through experimentation. The designer tries something, sees what happens, and adjusts. Each iteration adds information. The process is not random. It is guided by feedback and testing. The designer knows what they are trying to learn. They design the test to answer a specific question. Iteration can happen at any scale. A quick sketch reviewed with a colleague is an iteration. A full usability study with twenty participants is another. The scale depends on the question and the resources. The key is the loop. Design, test, learn, repeat. The loop never ends. It just reaches a point where the design is good enough to ship.

Iteration cycle

1. Design — create a version of the solution
2. Prototype — make it tangible enough to test
3. Test — observe how users interact with it
4. Learn — identify what worked and what did not
5. Revise — apply the learning to the next version

Iteration is how design improves. Each cycle makes the next version better. The process is the point.