Gram-positive bacteria attach proteins to the cell surface to mediate interactions critical to bacterial virulence, facilitating host cell adhesion, attachment to prosthetic devices, and homotypic interactions in protein-dependent biofilm. The cell surface is a spatially competitive space, driving evolution of unusual protein folds to facilitate functional domain exposure. High-identity repeats are a characteristic feature of a group of adhesive protein structures. Through structural and biophysical analyses, we have revealed the structure of three such monomeric surface proteins from Gram-positive bacteria. In repetitive contexts, we determined these monomeric repeats can form rod-like highly anisotropic structures on the nanometer scale, demonstrating an elegant solution to the display of functional domains at the host:microbe interface. Long-read sequencing from the Public Health England NCTC3000 data set identifies repeat domain topology in >1,500 proteins from Gram-positive and Gram-negative bacteria, with >50 featuring strain-dependent variation in repeat number. Combining the observed repeat number variation with the characterization of linearly extended rod-like topologies, we have named this group ‘Periscope Proteins’, revealing a widespread mechanism of surface variation in bacteria [1].