D: [
# ANCHOR: diagram
arrow right 200% "Markdown" "Source"
box rad 10px "Markdown" "Formatter" "(mdbook)" fit
arrow right 200% "HTML+SVG" "Output"
arrow <-> down 70% from last box.s
box same "Pikchr" "Preprocessor" "(mdbook-pikchr)" fit
# ANCHOR_END: diagram
]
box color White fill White rad 10px behind D \
    width D.width+20px height D.height+20px at D.center