There was a sturdy ram with a pair of thick horns upright on its head.
It strutted about proudly and saw a fence built with bamboo and wood in front, which blocked its way. It cast a sidelong glance at the fence, lowered its neck and lunged at it, hoping to knock it down. The fence remained intact, but the ram injured its own horns.
If it had not injured its horns, the ram would have persisted obstinately in butting against the fence, even against the spokes of a wheel, until it bled with a fractured skull.
As a result, with its horns caught in the fence, the ram could neither advance nor retreat but bleat helplessly.