Scratch one Harvard then, Danny. Easy come, easy go. Pity they didn't crate it up and bury it. Worth millions now, by all accounts!
Your mention of the Signal Square stirs ancient memories of learning about them as an RAF CCF cadet at school; of red squares with and without diagonals, white dumbbells with and without black bars or red L's, red right angled arrows and of course white rotating T's. Other variants existed as well, listed here:-
Signal Square
Possibly one of the longest lived items of aviation infrastructure?