In the diagram below the two pieces are shown. It is very important to chose the distance between the notches quite carefully. If the distance between the notches is to small or to large the puzzle will not fit. 

In the design graph below a suggestion for decent dimensions between the notches (MG and MJ) are given. These dimensions are not that strict as the other values in the table, so you could experiment a bit when making this puzzle

Design graph

For an explanation about the use of this design graph click here.