Boxes are rectangles, junctions are small circles, outer ports are shown at the boundary.
Examples
w <- uwd(c("s", "r"), c("s", "i"), c("i", "r"))
cat(uwd_to_dot(w))
#> graph UWD {
#> rankdir=LR;
#> J_1 [label="s" shape=circle width=0.3 style=filled fillcolor=gray90];
#> J_2 [label="r" shape=circle width=0.3 style=filled fillcolor=gray90];
#> J_3 [label="i" shape=circle width=0.3 style=filled fillcolor=gray90];
#> B_1 [label="Box 1" shape=box style=filled fillcolor=lightyellow];
#> B_2 [label="Box 2" shape=box style=filled fillcolor=lightyellow];
#> OP_1 [label="" shape=diamond width=0.2 style=filled fillcolor=black];
#> OP_1 -- J_1;
#> OP_2 [label="" shape=diamond width=0.2 style=filled fillcolor=black];
#> OP_2 -- J_2;
#> B_1 -- J_1;
#> B_1 -- J_3;
#> B_2 -- J_3;
#> B_2 -- J_2;
#> }
# \donttest{
to_graphviz(w)
# }