Interesting. I would guess those are quadrilaterals, but neither squares nor rectangles. Also, how do you draw the 'quadrilaterals'? A straight line on the 'standard' map or going along the shortest route?
Straight lines along the shortest route, which would appear as a curve on Mercator-projected maps. As they are lines along a curved surface (this planet), the quadrilaterals' edges are, strictly speaking, 3-dimensional curves.