Recently, I had a great experience when I was teaching the students triangle-related vocabulary. I had divided students into groups of 3 and given each group a square piece of white paper. The students were asked to fold their paper to show different terms relating to triangles (such as altitude, orthocentre, etc.) and to present these terms to the class. Even though the students were presenting the same terms as other groups (as a way of practising their English), each group found a unique way to express the words, which was great to see in an ESL classroom.