Well considering this is my first attempt at a RIMS...the elevated is the HLT, the one to the left of it is the MLT and the far left is the BK. I designed it so I only had to use one pump and two 6' silicione hoses with SS QD's for wort transfer.
The HLT drains into the MLT via gravity through a copper manifold (sparge arm not attached in photo). In theory I could have used a single tier design with a single pump, it would just require more SS QD's. I have a sightglass on every keggle just because I am OCD and wanted to keep them uniform in appearance.
Mind you I have brewed extract and never AG....I read and read and read and decided this was the best design. I anticipate some problems, but nothing major.