The Gallo-Roman Dodecahedron and Hollow Icosahedron as Non-Verbal, Tactile Mnemonic Trade Counters: A Unified Framework

The Gallo-Roman dodecahedron (~130 cataloged specimens) and its hollow icosahedral counterparts remain unassigned in classical archaeology. Prior attempts to model these artifacts as surveying instruments, rangefinders, astronomical calculators, or textile tools fail under physical scrutiny—particularly due to the complete absence of written markings, numerals, or standardized metric dimensions across the corpus. This paper establishes a unified cognitive-ergonomic framework, modeling both hollow polyhedral variants as non-verbal tactile memory counters used by elite provincial merchants (negotiatores) and guild leaders (collegia). Engineered to bridge Roman duodecimal (Base-12) monetary/weight structures with native Celtic/Germanic vigesimal (Base-20) tally traditions along the Rhine-Danube Limes, these devices relied entirely on physical morphology—asymmetric hole gradients and differentiated corner knob clusters—to execute rapid, non-verbal batch auditing without requiring written characters or visual inspection.