These are photos of bacterial colonies (Pseudomonas aeruginosa), which wrinkle up to optimize oxygen intake. Each colony pictured is a different mutant. The colonies were grown on agar plates supplemented with Congo red and Coomassie blue dyes. The dyes bind to proteins and extracellular matrix, and differences in coloration are the result of differences in protein and ECM production. Photos were taken with a digital microscope, but appear here rescaled to a uniform size.