Flowchart

Code
%%{init: {"flowchart": {"htmlLabels": false}} }%%
flowchart LR
subgraph "One"
  a("`The **cat**
  in the hat`") -- "edge label" --> b{{"`The **dog** in the hog`"}}
end
subgraph "`**Two**`"
  c("`The **cat**
  in the hat`") -- "`Bold **edge label**`" --> d("The dog in the hog")
end