Antique 1920's Teaching Sphere Wood Geometry Surface and Volume Steampunk Style

Wood Geometry Surface and Volume Teaching Sphere 1920's Antique Steampunk Style.   Pre-owned and in good condition. Wear and minor fading consistant with age.   Used as a tool for many schoolhouse years as a multidimensional geometry teaching sphere.  The item has a warm patina to the wood surface. Original notes displayed on the sphere and inside. It opens to many different shapes and options.  Dimensions are: Height: 5 in (12.7 cm)Width: 5 in (12.7 cm)Depth: 5 in (12.7 cm).  Please review pictures for additional information.