Projects项目
Selected work.精选作品。
Each record says why the thing was made, how it is put together, what went wrong, and where it stands.每份记录都写四件事：为什么做，怎样搭起来，哪里出了问题，现在停在哪。
PLC work is part of the engineering background. It will get its own record when there is a specific system worth describing. Until then it stays off this list.PLC 属于工程背景。等有一套值得写下的具体系统时，再单独开一篇。在那之前，不放进这张清单。