.PS 4.0i
.ps 20
## figure A-1
boxwid = 5 * boxwid
boxht  = 2 * boxht
##
B1:     box
B2:     box with .n at (B1.s.x, B1.s.y-lineht) "PRESENTATION"
B3:     box with .n at (B2.s.x, B2.s.y-lineht) "SESSION"
B4:     box with .n at (B3.s.x, B3.s.y-lineht) "TRANSPORT"
        line from B1.s to B2.n "\ data structures" ljust
        line from B2.s to B3.n "\ dialogues" ljust
        line from B3.s to B4.n "\ circuits" ljust
##
boxwid = boxwid / 5
boxht =  boxht / 2
B1a:    box with .nw at (B1.nw.x+boxwid/2, B1.nw.y-boxht/2) "ACSE"
B1b:    box with .n at (B1.n.x, B1.n.y-boxht/2) dashed "$\ldots$"
B1c:    box with .ne at (B1.ne.x-boxwid/2, B1.ne.y-boxht/2) "ROSE"
	move to (B1.se.x+linewid/2, B1.se.y); \
	"\begin{tabular}[c]{cc} A&\\ B&S\\ S&Y\\ T&N\\ R&T\\ A&A\\ C&X\\ T& \end{tabular}" ljust
##
.PE