When Lucretius says "put a system of mirrors in the house. good to find hidden things. friend mirror system": that's Cassius in Pompey's house.
[De rerum natura 4.302ff trans. Kelk:
"An image might
From glass to glass some few times be passed round,
Because whatever objects can be found
Hiding back in the house, though far removed
In twists and turns, yet they can still be proved
Able to be brought forth and seen to be,
Via each glass, in the vicinity. "]












