At this stage, aesthetics are ignored entirely. If you are inventing a new type of drone propeller, your POC might be a motor duct-taped to a wooden stick. If you are building a new app, your POC might be a spreadsheet that calculates the backend logic.
Do not test a functional prototype for durability with a graphic designer. Do not test a visual prototype for color with a mechanical engineer. Match the prototype to the expert. And for gods sake, do not ask your mother to test anything—she loves you too much to criticize you. Prototype
Paper, cardboard, tape, whiteboards, wireframes. Goal: To validate broad concepts and flows. Best for: Early brainstorming and user journey mapping. Example: Sketching the interface of a banking app on a stack of sticky notes. You slide the notes around to simulate screen changes before writing a single line of code. At this stage, aesthetics are ignored entirely
Validating risk, user testing, stakeholder alignment, internal pitching. Worst for: Predicting manufacturing cost, final performance benchmarks, or legal compliance. Do not test a functional prototype for durability
Even with great tools, teams fail. Here are the most common traps.