.

  I think HN strips starting blank lines,
  but it may work when done after a line with some char like: .

edit test:

         0 ┤ ╭───╮ Homer made burger
           │ │ ● │ ╭───╮ McBurger
         2 ┤ ╰───╯ │ ○ │  ╭─────╮
           │       ╰───╯  │  *  │ Food truck burger
         4 ┤              ╰─────╯
           │
           │                         ╭─────╮
         6 ┤                         │  ■  │ this was edited btw
           │                         ╰─────╯                   ╭─────╮
         8 ┤                                   Hairport burger │  ▲  │
           │                                                   ╰─────╯
        10 └┬────────────┬───────────┬────────────┬───────────┬────────────┬
           $0           $8          $16          $24         $32          $40

Works fine for me, even after multiple edits the formatting stays the same ¯\(ツ)/¯

Thanks - it was HN stripping starting blank lines (incl. after an edit).

foo

  aa
  bb