The law of stroke:

1. Any connected graph composed of even points can be drawn with one stroke. When drawing, you can start from any even point, and finally you can finish drawing with this point as the end point.

2. Any connected graph with only two singularities (the rest are even points) can be drawn with one stroke. When drawing, one singularity must be the starting point and the other singularity must be the end point.

3. I can't draw any other paintings.

Note: Points connected by odd (odd) edges are called singularities; A point connected with an even edge is called an even point.

Therefore, the word "Tian" has four singularities and five even points, and it is impossible to complete it at once.