.PS
.ps 20
## figure 16
boxwid = (5 * .75) * boxwid
boxht  = 1.5 * boxht
##
B2:     box shaded "\normalsize PRESENTATION"
B3:     box with .n at (B2.s.x, B2.s.y-lineht) "\normalsize SESSION"
B4:     box shaded with .n at (B3.s.x, B3.s.y-lineht) "\normalsize TRANSPORT"
        line from B2.s to B3.n "\ dialogues" ljust
        line from B3.s to B4.n "\ circuits" ljust
##
.PE