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.