Here is a rolled oat. It's a minimally processed oat groat that is steamed, then flattened with a roller, then lightly toasted for stability. Oats are the 7th most grown cereal grain in the world, behind maize, rice, wheat, barley, sorghum and millet. The rolled oat in the picture has dimensions 9.1 by 6.6 mm.
Equipment used: Canon EOS Rebel T5i with a standard zoom lens (EF-S 18-55 mm) on a 49 mm long extension tube.