1. \" DS - display. If .DS C, center; L, left-adjust; I, indent. 2.de DS 3.KS 4.nf 5.\\$1D \\$2 \\$1 6.ft 1 7.ps \\n(PS 8.if \\n(VS>40 .vs \\n(VSu 9.if \\n(VS<=39 .vs \\n(VSp 10.. 11.de D 12.ID \\$1 13.. 14.de CD 15.XD 16.ce 1000 17.. 18.de ID 19.XD 20.if t .in +0.5i 21.if n .in +8 22.if \\n(.$ .if !"\\$1"I" .if !"\\$1"" .in \\n(OIu 23.if \\n(.$ .if !"\\$1"I" .if !"\\$1"" .in +\\$1n 24.. 25.de LD 26.XD 27.. 28.de XD 29.nf 30.nr OI \\n(.i 31.SP \\n(DVu 32.sp \\n(DVu 33.. 34. \" BD - block display: save everything, then center it. 35.de BD 36.XD 37.nr BD 1 38.nf 39.in \\n(OIu 40.di DD 41.. 42. \"DE - display end 43.de DE 44.ce 0 45.if \\n(BD>0 .DF 46.nr BD 0 47.in \\n(OIu 48.KE 49.SP \\n(DVu 50.sp \\n(DVu 51.fi 52.. 53. \" DF - finish a block display to be recentered. 54.de DF 55.di 56.if \\n(dl>\\n(BD .nr BD \\n(dl 57.if \\n(BD<\\n(.l .in (\\n(.lu-\\n(BDu)/2u 58.nr EI \\n(.l-\\n(.i 59.ta \\n(EIuR 60.nf 61.DD 62.in \\n(OIu 63.. 64