This design was prompted by Bob Cater in Wales. He was describing the Visconti Divina Proportione fountain pen which comes with a lovely three legged calliper.
A similar calliper could be useful in product design courses so students can measure existing products and determine the proportions of their own designs.
The ZIP file is attached containing a PDF, Creo models and a dxf for laser cutting. Start by reading the PDF.
If you use this in your teaching please post feedback and examples.