The three-dimensional topography data recovered by gel-based profilometry can help you make unique observations on the surface texture of biological surfaces, such as the armor-like ganoid scales of Polypterus endlicheri (see ‘Materials design principles of ancient fish armour’ by Bruet et al. http://go.nature.com/2ivXi8I for more information on poylpterus armor). Using software for surface analysis, height profile lines can be generated (shown above), along with a variety of roughness and surface measurements (not shown). This topographic data is crucial for understanding how biological surfaces interact with their environments. Images: Dylan Wainwright and George Albert Boulenger.