Likely an art school exercise, though it's also got a bit of the feel of a trench art piece to me. I take it as a portrait of a woman, in pretty short shorts, who also looks a but as if she might be wearing an officer's cap...though I could well be seeing things! Whatever the case, I like the manner of it a lot (better and a bit more sculptural and refined looking in person than in photos) from all those lines for the folds of cloth to all those tiny pin pricks animating the ground. Mid-century I believe, on a piece of thin copper--heavy enough to endure but thin enough to bend. Signed B.L.M at lower right. 

6 x 3 1/2" and in good vintage condition.