Writing or Writings on the walls.

[Ashraful Haque]

"You can learn a lot about the ancient times from the writings/writing on these walls." (Multiple walls)
"The writings/writing on this wall could help us learn more about the case." (Writing/s on a single wall)

 

[emsr2d2]

Use "the writing". Although it can be countable, it's used uncountably in your context.

 

[jutfrank]

The plural countable sense means that there are multiple bits of writing, probably in different places on the wall and possibly by different writers. I think the context is fine for that sense.

 

[BobK]

Are you talking about graffiti? If so it would help if you used the word.

 

[BobK]

PS 'The writing on the wall' is a strong collocation. Etymologically it refers to Belshazzar's Feast (when there was a real wall where prophetic wring appeared), but today it vcan be used to refer ti any (even implied} prediction or realization: 'When sales figures were down for the third quarter in a row, he knew the writing was on the wall'.

But archaeologists (and more generally historians) can tell a lot from graffiti (informal writing and drawings not necessarily intended to be permanent).

 

[SoothingDave]

There's a sense of doom, too. The "writing on the wall" is never good news.

 

[Ashraful Haque]

Please let me know if I got it.

Multiple walls and many writers/messages:
When a revolution takes place in a country. People tend to write on walls. They write about the changes they want, the reason they are protesting and ready to die for.

I'm guessing in this context 'writings on the walls' would be the correct thing to say since we're talking about multiple walls and many different writers.

Single wall but many different writers/messages:
'Writings on the wall.'

Single wall with a single massage. Doesn't matter how big or small the message is (for example an entire poem/ an impactful quote by Nelson Mandela)
'Writing on the wall.'

 

[Tarheel]

I might say:

They write about the changes they want, the reason they are protesting, and what they are willing to risk their lives for.