Tank stand question

[Jshakour]

I have a 30g and two 10g, I would like to build a stand for all three to rest on. I was thinking the 30g which is 36" left to right and 12" front to back on the bottom of the stand and the two 10g on the top. The problem is the depth, the 10g are only 10" and the 30g 12".

So how can I design a stand to accommodate all three? I'm sure it is something as simple as adding another 2x4 across the back for the 10's, but i wasnt sure.