A series of setting lines from the 4th century BC tholos tomb at Starosel (Bulgaria) reveal a story about an architect faced with an unusual task: adapting the Doric order to the interior design of a circular burial chamber. The tholos stylobate in Starosel preserves incised setting lines, which served as guides to the builders. I argue that these lines also represent two versions of the building plan. The implemented second version reflects a correction, in which the intercolumniation at the (...) entrance was extended, and the remaining intercolumniations were equalized. The miscalculation that prompted this correction, and the subsequent issues in the design of the Doric interior expose the complex logistics involved in this ambitious and innovative building project. (shrink)