The red on the corners appears to comes from being painted on the underside of the glass
I'd guess 1960s/early 70s
making it feel like quite a singular thing
In addition to variation in the shape of the legs and feet
19th Century Small Size Handmade School Slate with Charming Etched Monogram, Stars and Shapes weathered chain The red on the cornersLots of different reasons for falling in love with antique school slates beautiful old mends, carvings into the wood, or, in this case, etchings into the surface of the slate itself. It's a lovely, unusually small, 19th century example to begin with, with wooden pegs at the jointed corners, but it is the work of R. P. T that really sold me, between those dimensional block initials, and cubes for periods, and stars and shapes and flourishes