two sockets under another board for his two tenons  <EXO26  -:19 
>

two sockets under another board for his two tenons  <EXO36  -:24 
>

two sockets under one board for his two tenons  <EXO26  -:19 >

two sockets under one board for his two tenons  <EXO36  -:24 >

two tenons                              <EXO26  -:17 >