| .	\"DS - display.  If .DS C, center; L, left-adjust; I, indent. | 
 | .de DS | 
 | .KS | 
 | .nf | 
 | .\\$1D \\$2 \\$1 | 
 | .ft 1 | 
 | .if !\\n(IF \{\ | 
 | .	ps \\n(PS | 
 | .	ta 5n 10n 15n 20n 25n 30n 35n 40n 45n 50n 55n 60n 65n 70n 75n 80n | 
 | .	ie \\n(VS>=41 .vs \\n(VSu | 
 | .	el .vs \\n(VSp\} | 
 | .. | 
 | .de D | 
 | .ID \\$1 | 
 | .. | 
 | .de CD | 
 | .XD | 
 | .ce 1000 | 
 | .. | 
 | .de ID | 
 | .XD | 
 | .if t .in +0.5i | 
 | .if n .in +8 | 
 | .if \\n(.$ .if !"\\$1"I" .if !"\\$1"" .in \\n(OIu | 
 | .if \\n(.$ .if !"\\$1"I" .if !"\\$1"" .in +\\$1n | 
 | .. | 
 | .de LD | 
 | .XD | 
 | .. | 
 | .de XD | 
 | .nf | 
 | .nr OI \\n(.i | 
 | .sp \\n(DVu | 
 | .. | 
 | .de BD \" block display: save everything, then center it. | 
 | .XD | 
 | .nr BD 1 | 
 | .nf | 
 | .in \\n(OIu | 
 | .di DD | 
 | .. | 
 | .	\"DE - display end | 
 | .de DE | 
 | .ce 0 | 
 | .if \\n(BD>0 .DF | 
 | .nr BD 0 | 
 | .in \\n(OIu | 
 | .KE | 
 | .sp \\n(DVu | 
 | .fi | 
 | .. | 
 | .de DF \" finish a block display to be recentered. | 
 | .di | 
 | .if \\n(dl>\\n(BD .nr BD \\n(dl | 
 | .if \\n(BD<\\n(.l .in (\\n(.lu-\\n(BDu)/2u | 
 | .nr EI \\n(.l-\\n(.i | 
 | .ta \\n(EIuR | 
 | .nf | 
 | .DD | 
 | .in \\n(OIu | 
 | .. |