The cow tools are for a mothering class.Someone claims to have figured it out: "a hay bale saw, a wayward calf corraller, an udder assistance device, and cud." The cow is teaching other cows how to raise their calves.
Alternatively, the cow made the tools in order to be more like humans.As we've seen in this strip, cows are capable of doing many human-like things, such as eating meat with silverware. It's entirely possible that the cow was just trying to copy primitive man, leading to the creation of the cow tools. She could also have gotten inspiration by her farmer, suggested by the barn in the background. The saw-like tool could've been inspired by a saw that was in the barn, and the long, curved stick could've been her version of a hoe or rake. The other two tools I'm not that sure about, but the "handle" poking out of one suggests that that one is used for pounding things, like a hammer.
The man walking under a piano was a Complete Monster who had ignored his last possible epiphany and was now a broken hnau, just some evil going forever like a machine.