.nr _C \n(.C
.cp 0
.ftr CW CR
.ftr C CR
.ftr CX CBI
.ftr H UR
.ftr HR UR
.ftr HB UB
.ftr HBI UBI
.ftr HI UI
.ftr HO UI
.ftr HX UBI
.\" This is designed so that \(ul, \(rn and \(br form corners.
.if !c\[br] .char \[br] \Z'\v'.25m'\D'R .04m -1m''
.if !c\[ru] .char \[ru] \Z'\v'-.02m'\D'R .54m .04m''\h'.5m'
.if !c\[rn] .char \[rn] \Z'\v'-.77m'\D'R .54m .04m''\h'.5m'
.if !c\[ul] .char \[ul] \Z'\v'.23m'\D'R .54m .04m''\h'.5m'
.cp \n(_C
