Beginnr level simple lithic puzzle. A modern knapped raw piece of Texas flint was reduced with the early shaping flakes saved, as they might appear in the archaeological record on a production/raw material site.  This example here is the rough out for a BURIN tool core. This is how it might appear when reducing to the PREFORM stage for lighter weight travel. When new students piece such puzzles back together, it helps them to understand how flint tools are flaked and reduced, and how each flake represents a part of the process.  This particular puzzle represents the most simple form and example to work, and contains 9 pieces to refit.  A water soluble glue or a rubber band, or simply by hand, is a way to hold together if needed, and this process has proven to be a great aid for new archaeology students who are not yet familiar with stone tool technology.  The flakes fit back on the core only in order of their production, and therefore teaches the process.  They place together with almost molecular fit, so flush its hard to see the broken line.