[pharke]

Just taking a look at Dungeon Magazine on archive.org and it seems that crosshatching in walls is pretty common, at least in the early editions.

https://archive.org/details/Dungeon_Magazine_002/page/n25/mo...

https://archive.org/details/Dungeon_Magazine_002/page/n45/mo...

https://archive.org/details/Dungeon_Magazine_002/page/n51/mo...

https://archive.org/details/Dungeon_Magazine_003/page/n31/mo...

https://archive.org/details/Dungeon_Magazine_003/page/n41/mo...