Events lay themselves out in lines — rows of cars, stalls, tents, pens, chairs — and that repetition is free composition. Use the rows as leading lines that pull the eye, and the gaps between them as frames for a person walking through.

Where it works: car shows, markets, craft fairs, county shows, festivals — any event with an organised layout.

Best time: early, before the crowds fill the aisles and hide the geometry.