About the masks
Facial recognition is encoded, or acquired, from birth. Newborn infants will stare at a face longer than any other pattern. A face may mean mother, milk, or passage. The found masks pictured on this site are bog shoes (c.1900) used to keep horses from sinking into the mire, while working or crossing through.
Horses, in war, also wore gas masks. As did dogs, but not homing pigeons. The cages, however, were gas-proof.
Post-traumatic stress is a memory disorder, a failure to forget. One symptom is repetition. Another is seeing or hearing things that are not there.
What you are looking at are horseshoes. Place one above your door for luck.