Extendable shelf system (shoe shelf, table shelf, desk organizer)

I needed a table shelf so I created an extendable shelf system. 

• For 20 mm wood boards of any legth and width (tested with 400 mm width)
• Two sizes - 120 mm / 170 mm shelf spacing for 200 mm / 250 mm brint beds
• Shelf height = number of side panels to print

Assembly

• see last image
• 8x wood screws per shelf level + 2 for the feet (M4 x 30)
• pre-drilling recommend

Printing

• any material (depending on load requirements)
• no supports 
• 6 Perimeters recommended for stability