Two columns of users, with lines joining each on the left to each on
the right that for which the channel has the <#1300#> valve<#1300#> open.
#figure1301#
Figure: Floor Control
An open floor has all lines (except horizontal) filled in.
A 2D matrix, with all users listed along the top, and down the left.
An entry is then coloured differently for an open or closed valve.
#figure1305#
Figure: Floor Control
As shown in #fnfl2#1308>, an open floor has all entries except the diagonal filled
in.