This is to examine students' spatial thinking and imagination.

From the front, it seems that students are guided in this way. From the front, there are three squares. What about the bottom two? There are 1 squares on it, and look at the word "7" written at the back. Then ask the students to find the three squares in front of the word "7" and put them in the top position, which is more enlightening and enlightening. Form a spatial graph, then show the actual model to the children to impress them, and finally let the children draw a left view.