i would say with friends because with friends you are more emotionally attatched and wanting to beat them. Plus there is some fun involved and when you are with someone you know rather than strangers you feel more confident because you know some of their weaknesses and some strengths. Therefore you would be able to have more of an advantage in a race with friends rather then an event farther away.
Unity is when all the elements in a work look as though they belong together. Pattern is a two-dimensional, decorative visual repetition. It uses the art elements in planned repetitions or random repetitions to enhance surfaces of paintings, drawings or even sculptures.