Design either a wooden, bamboo or metal sheet shelf-like structure

I'm looking for a designer to design a 3 tiered (ground to eye level high) wooden structure for use inside a greenhouse for snail farming.

*Properties:
-1) Pyramid shaped with total length of 4 meters and total height of 2 meters (including upper deck curtain height)
-2) Upper Deck: Larger snails are unable to access the middle deck. (4*1m)
-3) Middle Deck: Medium sized snails are unable to access the lower deck. (4*1.5m)
-4) Lower Deck: The smaller snails after hatching can move from the upper deck through the middle deck to the lower deck to avoid competition for food. (4*2m)

*Considerations:
-1) Each deck has vegetation
-2) Each deck is designed to prevent absolute snail escape (wire mesh, nets, funnels, flaps, etc may be used)
-3) Each deck should also have a feeding surface of sought where powdered feed can be spread along the length
-4) Each deck is designed to also have vegetation get water access from sprinklers
-5) A plastic or net curtain can be hanged in the centre along the length so that snails may hang vertically as well.