The ```
*unit-transform*
```

variable holds the list ```
(1 0 0 1 0 0)
```

which is the unit transform I, such that X = XI, where X is a 3-vector. Graphics ports are initialized with the unit transform in their graphics state. This means that port coordinate axes are initially the same as the window axes.

LispWorks CAPI Reference Manual - 11 Apr 2005