This is a bacterial biofilm scraped from the surface of the tongue and imaged using CLASI-FISH. Human epithelial tissue forms a central core (gray). Colors indicate different bacteria: Actinomyces (red) occupy a region close to the core; Streptococcus (green) is localized in an exterior crust and in stripes in the interior. Other taxa (Rothia, cyan; Neisseria, yellow; Veillonella, magenta) are present in clusters and stripes that suggest growth of the community outward from the central core.