A combination of previous rules makes new sophisticated rule.

This example shows a case when 2s are put in between two 3s
in diagonal line.
Any number of 2s can be put between 3s. There are two 2s in this example. 


Let's start by assuming a corner of above 3 has two lines in Lshape as in this figure. 


By the "rule of diagonal 2s," this pattern will be copied to below "2s,"
and the Lshape corner of "2" touches a vertex of below "3".
Since the Lshape line is touching a vertex of 3, you cannot draw lines on two edges of "3" linked to that vertex. This situation conflicts with the rule of this puzzle. Therefore, you cannot have Lshape line on that corner. Only one edge can have a line here. 


And the Lshape lines will be drawn at the top left corner of above
"3", and the line will be extended to the bottom right vertex toward
next "2".
Now, by the "rule of diagonal 2s," a line comes to 3 from star marked vertex. So the two edges on the other side can have lines. 

When there is a pattern of 2 and 3 placed as "32..23" diagonally, 3s at both ends of this pattern will have Lshape lines on their outside edges.
Note that the pattern of "diagonal 3 and 3" is a special pattern of this case.
Rule of diagonal "32..23"  
