Unintentional, facelifted, duckface.

I would guess they used wood pegs either end to make it durable. Wood doesn’t preserve as well and stone.

There’s also no sense of scale. To me it looks like a roller skate. Shaped like a sandal, wider wheel base at the front for stability and it could have have leather or twine round the back of the heal. I could be totally wrong but that was my thinking when looking at it.