.PS
C1: box wid 1.5 "lpr -Pmain";

B1: box wid 1.5 "main" ":ss=s1,s2,s3" with .w at C1.e+(.5,0);

P1: box wid 1.5 with .w at B1.e+(.5,0) "s1:";
P2: box wid 1.5 with .n at P1.s+(0,-.5) "s2:";
P3: box wid 1.5 with .n at P2.s+(0,-.5) "s2:";

arrow from C1.e to B1.w;
arrow from B1.e to P1.w;
arrow from B1.e to P2.w;
arrow from B1.e to P3.w;

"All Queues on Same Server" ljust at C1.s+(0,-.5);

.PE
