Six tactile printable token STL designs with validation

Design six original tactile identification tokens as printable STL assets. Each has a 24 by 24 millimetre base, flat bottom and a distinct raised geometric symbol: parallel bars, concentric squares, cross, zigzag, dots, spiral-like path. Each token must be one closed connected solid, not overlapping disconnected meshes. Deliver six STL files, editable generation source, an SVG contact sheet and a dependency-free mesh validator. Validate undirected edge incidence of exactly two faces, connectedness, finite coordinates, bounding boxes and consistently oriented positive volume. Report dimensions, triangle counts and volume for every token; choose simple robust manufacturable geometry. These are adult maker prototypes; no certification, accessibility efficacy claim or physical print test. Deliver English materials, original content and offline reproducible checks. The artifact is the product; no web application or external service. Make reasonable reversible design choices independently.