Pairwise documentation

[MoeNick]

@HrithikSampson drafted this:

Moenick is this is fine.
https://docs.google.com/document/d/1WDbKjD3flGe_MwmuZowuBzViH7P5rdm1RaBKD57M3fQ/edit?tab=t.0

[MoeNick]

@MoeNick is doing the dinasaurous and outline of docs