What is it for?
The weird setup comes from having 3s packs arranged along the walls of a box-shaped robot, instead of grouped together in a single pack. These mini packs need to be in parallel with each other. The way it works out, the packs end up forming the shape drawn above.
This is the thing: A schematic is a logical representation of a physical layout; what you see in a schematic does not have to match (and usually can't!) the physical layout of the circuit itself. For instance, take a look at the schematic for the Arduino, and compare it to the physical PCB - I can guarantee you nothing is in the same place as it is on a schematic.
This doesn't only apply to circuits, either - any schematic diagram (process diagrams, flow charts, etc) is typically representing a logical layout (generally in a manner that makes the intent/usage/operation of the device/system/process clearer to a human) of what could be a very complex physical layout (you want to see complex - look into industrial plant process controls and systems, like that used for refineries, assembly lines, etc; even the schematics for such a system are pretty dense, but they certainly don't represent the physical layout of the plant).
Your "schematic", as drawn, actually does the opposite of what a schematic should do; namely depicting how the system as a whole works in a clear fashion. If you illustrated an entire robot system in this manner, it would quickly become nearly impossible to figure out and follow.
Not that it hasn't been tried in the past, though; pick up really old "popular electronics" magazines from about 1950 or older, and you'll see a ton of articles on radio chassis wiring illustrated with physical wiring layout and assembly diagrams (sometimes with a real schematic, sometimes not!). I will grant in some of these cases it was likely important to lay out some of the items carefully, and show how to wire them, because they were using point-to-point wiring/soldering techniques (PCBs weren't on the scene yet), and if you wired things in the wrong order, you might not be able to solder something else because another component or holder was in the way...