Vitsoe606 hack 2a and 2b : Spruce shelves

Another 606 hack...
A simple wooden shelf. 

Spruce boards, stainless steel brackets and screws, bee/carnuba wax finish.
300mm and 200mm deep.
Two variants:
a) 912mm module width (end brackets)
b) extended width (sub brackets)


_{Note: no endorsement from Vitsoe should be inferred.}