More online searching for Triumph esoterica brought this up… a doodle watercoloured sketch of a Bonneville on page 17 of some ledger book. Nice quirky but detailed ink lines albeit a contorted angle of view.
Indeed Ledger Art is a form of visual narrative used by the Plains Indians from the mid nineteenth century on (itself an adaptation of Hide Painting though using available papers from large record keeping ledger books) Here’s a modern take on that with the use of horse power and Indian motorcycle horsepower…
geordiebiker.com 