Get obstacle to only cover one node

I have tried different settings, but I cant get walls to only cover the nodes they are on. Either they cover nothing or two rows of nodes.

Hi

Nodes are actually in the corners of those squares (it is more clear when you use 8 neighbors per node). What you are seeing in the editor is the connections between the nodes, not the outlines of them. So your walls are actually occupying just one row of nodes.