the difference between boys and girls

Today I was teaching my AP physics class and I did an activity that I've done for years in my advanced physics classes where students plot points on a poster with markers and draw arrows to indicate the amount of force they have calculated. This year, my class is small and 4 out of the 5 students are girls. They spent a full 5 minutes coordinating the color scheme of the dots and arrows to make sure they didn't have clashing colors and that the finished product would have a coordinated look. They pressured the sole male student to abandon his orange marker because it broke the color scheme. No such thing has ever happened in my boy-dominated classes.