Finding the Centrepoint:
1. Many of us would often mistaken that this unit has missing corners as shown, here:-
2. Other than cut-out an outline on a cardboard and balancing it on a pin, I use a quick eye-ball method to roughly equate the purple area (yes purple area is suppose to be the protrusion):-
3. I asked many people and often they felt that this unit has lots of missing corners as they felt that Para 1 above best reflect this layout.
4. But 80% of the time many never realise that as there CAN be missing corners, there can also be PROTUSIONS! Not always assume an odd shape layout always have missing areas.