Dean, if you mean changing the board. It used to be one of four 90º corners used with our old double track modular layout, see photo.
Modular0080 copy by
Mike Ruby, on Flickr
These corners went out of use when we changed to single track modules. I made one into a single track module, another became the corner on 23rd Street, I gave the third away and so this is the last which has been in the loft for a few years.
I widen them out to 18" the modular end standard, fit my leg sockets so it use my common leg design and make the track and wiring to the standard. This is easier than building a new module and a good bit of recycling as were 23rd Street's boards.