This design is commonly referred to as "Crown of Thorns" and the tips of each piece is made pointed.
Each intersection requires six separate pieces to interlock.
Each piece is square and normally quite small (3/16" is about right)
The cutouts at the intersections are two times thickness long; and one half thickness deep.
The locations of the slots depends upon what you are making.
Most often the intersections are about one inch apart.
Front View of a different assembly;
note the area between intersections
has been carved out slightly.
A typical 90 degree construction
An extensive four-position picture frame
Note the construction is at 45 degrees rather than the normal 90 degrees.
