Quadratic Diffusser Plans??

Can someone give me the details for a quadratic diffusser. I would like the well depths and the well width. The width stays the same but the depth varies from well to well. I have googled this topic and can't find any specific measurements.

I am talking about the slatted diffuser, not the one made out of peices of 2x2 wood.

I would like to build some for my room.Thanks for the help.