To extend to your comment, lightly examining a number of shells could also serve a few additional pedagogical functions: * Showing students that there are many

To extend to your comment, lightly examining a number of shells could also serve a few additional pedagogical functions: * Showing students that there are many shells that they could encounter. * Highlighting the differences. * Showing that there is a long history. * Showing that the history is still alive. * Showing that there is no one right way.