You know I love all things Froebel kindergarten, and this is a very scarce, c. late 19th century Froebel kingergarten "Gift 7", produced by J.L Hammett, Boston. The J.L Hammett  company was formed in 1863 by John Hammett, a school teacher himself, who is credited with inventing the chalkboard eraser. In 1890, Hammett sold the company to a group of Massachusetts investors, and in 1891 partnered with Milton Bradley of Springfield to produce the first kindergarten materials in the United States. 

Froebel's Gift 7, known as "Parquetry Tablets," was/is comprised of flat geometric shapes made of wood, plastic, or paper in contrasting tones, and was conceived as means of helping children understand that surfaces can be separate objects, to move from understanding solids to understanding flat surfaces, and to help children explore the world in a concrete way. I think it is likely that this box, filled four layers deep with two different types of triangles in three different tones of wood, was one box among several featuring other shapes, that together comprised an expansive Gift 7 set. 

Box 6 3/4 x 2 1/2 x 3/4. Box and "tablets" all in lovely antique condition, just missing a single larger sized triangle I believe. Unlikely you'll come across another set of these!