Tessellations

Fusion 360

1. Create a New Sketch:
   
2. Select the ground plane:
   
3. Make a centered rectangle 80 x 80:
   
4. Select the spline tool:
   
5. Make a nibble at the top:
   
6. Make a nibble on the left side:
   
7. Stop the sketch:
   
8. Extrude one of the nibbles:
   
9. Turn on Sketch 1:
   
10. Extrude the other two parts, making sure to create new bodies with each extrusion:
    
11. Select the top nibble:
    
12. Move it 80mm to the bottom:
    
    
13. Select the nibble on the left and move it 80mm to the right:
    
14. Select Combine from the modify menu:
    
15. Select all three pieces and click OK:
    
    
16. Create a sketch on the top surface:
    
17. Create an offset of -.4mm:
    
18. Turn off the body and Sketch 1:
    
19. Extrude the new profile. Make a copy to test fit: