.PS
.ps 20
##
lineht	=	2*lineht/3
## figure A-4
B1:	box "user-element" width 2*boxwid
B1a:	box invis with .w at B1.w
B1b:	box invis with .e at B1.e
B2:	box "ROSE" with .ne at (B1.se.x, B1.se.y-lineht)
B3:	box "RTSE" with .ne at (B2.se.x, B2.se.y-lineht) width 2*boxwid
B3a:	box invis with .w at B3.w
B3b:	box invis with .e at B3.e
B4:	box "ACSE" with .nw at (B3.sw.x, B3.sw.y-lineht)
B5:	box with .n at (B1.n.x, B1.n.y+boxht/2) width 3*boxwid \
	height boxht+B1.n.y-B4.s.y
##
	line from B1a.s to B3a.n
	line from B3a.s to B4.n
	line from B4.s to (B4.s.x, B5.s.y)
	line from B1b.s to B2.n
	line from B2.s to B3b.n
	line from B3b.s to (B3b.s.x, B5.s.y)
##
	line down from B5.s
	line dashed from (B5.w.x-linewid/2, B5.s.y-lineht) \
		    to   (B5.e.x+linewid/2, B5.s.y-lineht)
	move to (B5.e.x+linewid/2 , B5.s.y-lineht); \
	    "\ \ presentation service" ljust
##
.PE