Each of the objects required for the final circuit can be customized using parameters. These parameters default to useful values if they are not specified so it is often enough to simply use two or three parameters (say WIDTH and LENGTH). The other parameters are there in case special circumstances arise or fine-tuning is necessary.
A look inside a building-block object (a cascoded current-mirror in this case) shows the layout itself, plus additional text information regarding parameter values, object dimensions, and export terminal names ...
Web pages by Bryn R. Owen