Textbook of Engineering Drawing, Second Edition

22

·····y·····I·······I·······I·······I······y·····I·······I······y····y····y·····I·······I······y·····I·······1······y·····I·······I·······I·······I·······I·······1·······I······y····

······1·······1·······1·······1····+·····1·······1·······1·······1······-1--·····1·······1·······1·······1·······1······-1--·····1·······1·······1·······1·······1·······1·······1·······1······-1--··-

······I·······I·······I·······I···~····I·······I·······1·······1·····+······1·······1·······1·······1·······1·······1·······1·····+······1·······1·······1·······1·······1·······1····-