1.   Four men-at-arms rode alongside, and bringing up the rear was another monk herding a flock of sheep and goats.

2.   Instead, scientists are trying to discover if it is possible to create a robot that can quickly and competently herd a flock of ducks into a predefined position.

3.   Whether herding our flocks or chasing balls, dogs enrich our lives.

4.   Then, another little black-and-white dog herds another flock of sheep.