Defining a new window

Syntax: | `WINDOW { n { lowx lowy upx upy }}`

A new window is defined by the final four parameters with the command. The lower left corner will be `(lowx,lowy)` and the upper right corner will be `(upx,upy)`. These four parameters should be expressed as percentages of the full page, for example, `lowx = 50`, `lowy = 50` represents the centre of the world, while `lowx = 100`, `lowy = 100` represents the upper right hand corner.

Plotting units
Pre-defined windows