A prefabricated, modular shelter system that utilizes a series of identical enclosures, each made from barrier panels connected to define the shape of a modifiable dodecagon prism. The top cover of each enclosure can be flat or peaked at the center. The lightweight components are easily transported, assembled, disassembled, and/or re-assembled. The design allows two or many enclosures to cluster together without interstitial triangle prism volumes forming among them. Interior space within a cluster of enclosures can be increased, decreased, or re-arranged by simple addition, removal, or relocation of enclosures. Though the enclosures are each identical in shape, they can create a limitless variety of spatial areas and configurations, thus adapting to varied uses and requirements.