For a prison, it was old and forbidding.
It had damp spots, spots that appeared to move around the prison. At one stage the Governor complained about the damp spot in his office and ordered a major refurbishment.
Long time inmates used to place bets on where they might appear next.
The damp spots, of course, thought the prison was their domain and were not considerate of the inmates in any way. They moved about from boredom as much as anything else.
Lenny the Lag had a permanent damp spot in his cell. He was an interesting character, he’d killed four wives, and he was writing his memoir, “Innocent of All Charges”. Lenny’s damp spot conversed with the other damp spots, comparing notes, debating which spot might they move to next, except Lenny’s who was content, which in itself was usual for a damp spot.