right
B1: box "One"; line
B2: box "Two"; arrow
B3: box "Three"; down; arrow down 50%; circle "Hi!"; left;
spline -> left 2cm then to One.se
Macro: [
  B4: box "four"
  B5: box "five"
  B6: box "six"
] with n at 3cm below s of 2nd box

arrow from s of 2nd box to Macro.B5.n

spline -> from e of last circle right 1cm then down 1cm then to Macro.B4.e

box width Macro.width+0.1 height Macro.height+0.1 at Macro color Red
box width Macro.B5.width+0.05 \
    height Macro.B5.height+0.05 at Macro.B5 color blue
