First heading
Some plain text here.
Next paragraph
One empty line above

Second heading
Some plain text. Some bold text.
Number one
Number two
Number three
Para
First item
Second item
Third item
Para 2
Item a
Item b
Item c
Para 3

Third level head
4 whitespaces before and 3 in between next line
next line in between
2 tabs before and 3 in between next line
next line in between