12. Fill in the blanks in the figure with $1^{\sim} 9$ (the numbers 2 and 3 are already filled in), such that the number on the left is greater than the one on the right, and the number on top is greater than the one below. There are $\qquad$ different ways to fill in the blanks.
Analysis: 【Enumeration Method】A total of 16, as shown in the figure below:



Preserve the original text's line breaks and format, and output the translation result directly. 

Note: The phrase "as shown in the figure below" implies there is an accompanying image or diagram, which is not provided in the text. If you have the image, it should be included in the translation.