What is Figure 2.4 supposed to show?

I'm confused by Figure 2.4. If I'm understanding it correctly, shouldn't the column of numbers on the far right be 1, 4, 3, 8, 5, 12 instead of 1, 4, 4, 6, 6, 8?

<img width="866" height="464" alt="Image" src="https://github.com/user-attachments/assets/e4c19b5a-03c2-4d78-8cca-769e95a498f8" />