Ah, well now, loo walls: I recall from long since -- late-1940s iirc, a literary-historical dispute, I take it fortuitous, in two adjacent stalls in the Men's at corner of Oxford St & Charing X Road.

One read

One would think for all this wit
That Shakespeare had been here to shit
And after all that might be true
For Shakespeare had an arsehole too

The other

A man's ambition must be small
To write his name upon this wall
For even Shakespeare did not write
When he sat down to have a shite

Yer pays yer money...

≈M≈