Good design rarely happens in one pass. Iteration means repeating the design process to improve a concept. You sketch, prototype, test, and learn. Then you do it again. Each cycle refines the work. The first version is usually wrong in ways you cannot see until you put it in front of someone. Iteration is how you find out what is wrong and fix it. The approach comes from software development, where iterative cycles replaced the old waterfall model of building everything at once.

Iteration works best when cycles are short and feedback is fast. A paper prototype can be tested in an afternoon. A coded prototype takes longer but gives more accurate feedback. Designers often work in sprints, one or two weeks long, with a review at the end. The goal is not perfection at each step. It is learning. Each iteration should answer a question or reduce uncertainty. Some iterations fail. That is expected. A failed prototype that reveals a problem is more valuable than a polished design that hides one.

How iteration works

• Build a rough version quickly.
• Test it with real users.
• Identify what works and what does not.
• Revise and repeat.

Iteration is not endless tweaking. It is disciplined learning. At some point, the team has to ship. Knowing when to stop is part of the craft.