The method of determining the apex of public education in China is divided into three steps:

1, marking an existing vertex, that is, a point connecting three faces, with several marks.

2. Punctuate both sides of 123 in turn: 1 marked with 4 on both sides, 5 on both sides of 2, and 6 on both sides of 3.

3. Complete the remaining points: Now there are two 4' s, which connect three faces in total, so 4 is also a fixed vertex, and the vertex method can be used. On the periphery of the plane expansion diagram, the point 1 from the vertex 4 is the same point. We just found 4 according to 1, so we can't label it as 1. At this time, we found that the points on both sides of the two 4 were empty and unnamed, so we named the next number 7. Two 7s connect three faces in total, which is a fixed vertex, and both sides are marked with 8. Two octets only connect two faces, and the third octet is marked in the lower right corner. At this point, each number connects three faces and is labeled correctly.