O.k. I’m impressed. I didn’t expect you to get this far. Who can blame me?   Things haven’t always gone right for engineers. Sometimes they have worked out fine.   Other times they’ve quit before they even got a chance.   I hope you don’t quit….This is the last one.   {1, 13}   {11, 12, 14, 15, 16, 17}   {18, 19, 20}