blockquote with no whitespace before
>.
foo
blockquote with one space before the
>.
bar
blockquote with 2 spaces.
baz
this has three spaces so its a paragraph.
blah
> this one had four so it's a code block.
this nested blockquote has 0 on level one and 3 (one after the first
>+ 2 more) on level 2.and this has 4 on level 2 - another code block.