As we know, the board surface has 361 cross points.
众所周知，盘面有361个交叉点。
2
To find the surface element together with a normal vector, I would just take the cross-product between these guys.
为了找到带法向量的面元，我就取这两个的叉积。
3
A two-dimensional model of such a universe would look like a sphere. It's impossible to have parallel geodesics (straight lines on a curved surface) — the two lines will cross at some point.