I find it surprising that there's no free, high-quality printable basic walls downloadable anywhere - so I decided to create such and share them. These dungeon (or castle) walls are partially uneven structure, like they were very old, and this way work better as cave wall or cliff.
The photo below shows the walls in use; they have been altered a little bit after printing these walls but they are very close to these.
I've glued pieces of hardware (slags, bolts etc.) to the lower part of the walls to make them strudier; the paper I've used is thicker than normal, otherwise it would collapse easily. You can also glue support pieces inside walls, especially longer ones, and there's also templates for those with the longer wall piece sheet.
Always, be sure to check that the pieces fit in before applying glue. If you see severe issues with these models (I've modified the templates a bit after printing my own pieces so they'd look a bit better - they SHOULD be fine!) please let me know.
And if you want to post links to sites where you've posted pics of these walls in use, feel free to do so!
I've printed the walls at 300dpi - if the sheets won't fit completely on the print area, remember that those 'wings' aren't vital - you can cut these attaching surfaces without them. I've printed them with GIMP which allows better placing of the print area.
And one more thing - if you borrow these walls to other gm's, let them know that they aren't concrete - like you can see from the photo, too strong grip can give the a piece a dent.