IFS with Memory

Combinations of Lines

The reason is that the picture doesn't contain these lines:
The tables reveal this as well.
The vertical line in the middle of the picture is made from both the left and right side vertical lines.
Because 1 → 4 and 3 → 4 are allowed, the left side line gives the top of the middle line.
Note 1 → 2 and 3 → 2 are forbidden, so the left side line does not give the bottom of the middle line.
Because 2 → 1 and 4 → 1 are allowed, the right side line gives the bottom of the middle line.
Note 2 → 3 and 4 → 3 are forbidden, so the right side line does not give the top of the middle line.

Return to combinations of lines, 5.