Are L-shaped stones problematic towards the neighbor due to a slight slope?

The neighboring garage would be located lower than our property. Where his garage is at street level, that's where our L-shaped blocks begin. So the garage wall would directly adjoin our L-shaped blocks. That's not so easy to explain. I could imagine that there has to be a gap between his garage wall and our L-shaped blocks for air circulation or something similar. Do you understand what I mean?

then these mats come in between

as said, talking