 Diamond schools are often the product of the merger of a boys' and a girls' school, thus it is possible that at KS3 and KS4 girls and boys can be taught separately on different sites.It is a common feature that boys and girls combine outside the classroom in activities for academic trips and visits and in some co-curricular activities, such as choirs, orchestras and the Duke of Edinburgh Award scheme.Other coeducational schools adopt a "partial" diamond model in which certain subjects, e.g., science, technology, engineering, and mathematics (STEM) are taught to gender-segregated sets or classes, typically drawn from Key Stages 3 and 4 (Years 7 to 11).