Yesterday we went to Tyngsboro to celebrate the Fourth of July with friends, but most especially to celebrate our daughter's 50th birthday with her family. This is our third child to celebrate a 50th, the last two girls are not far behind. The birthday cake provided by Diane's best friend showed a hill with Diane on the downside. Diane laughed and asked me if I remembered the cake she had made for me on my 30th birthday? It…