(Intersection Machine under construction)
[b]Notes:[/b] The notation may need some cleanup. In my worksheets, [list] [*] a pair of vectors [math]\;{\rm x_1}, {\rm x_2}\;[/math] in an object definition should always be unit vectors, and [math]{\rm x_1}⊥{\rm x_2} [/math]. [*] a circumflex (hat) denotes the unit vector in a given direction: [math]\;\;\;{\rm \hat a} = {\rm a/|a|}[/math] [/list]