Neighbor assignment incorrect since commit 7f4a089 #4
Description
Since commit 7f4a089, the assignment for the left neighbor seems to be incorrect. Instead of the west neighbor node, the west / north west neighbor of a cell two levels above is assigned. Probably caused by some typo in the lookup table.
Since the unit test is passed for some reason, the corresponding unit test needs to be revised as well.
For now, we just go back to the previous (working) version.