Because I’m reading Ulrich’s book on Roman Woodworking I’m a little obsessed with representations these day. Bear with me, it might wear off. Or not. I like tools.
Anyway other than general awesomeness this mosaic caught my eye because of the log splitting frame saw at the very bottom. It reminded me of the log splitter in this relief.
Perhaps the bar on top is to allow a single worker to operate the saw or to act as a guide to keep it straight or both?
Liv Mariah Yarrow 
