Use "mulish" in a sentence

1. All the Campbells had similar streaks of mulish stubbornness

2. His mouth sets in a mulish line

3. At first he listened with attention to the excuses that Lorenzo Daza continued to offer in the name of his daughter, whom he defined as an intelligent and serious girl, worthy of a prince whether he came from here or anywhere else, whose only defect, so he said, was her mulish character