Single list tight:

- hi
- there
- fella

Single list loose in "paragraph mode":

- hey

- there

- partner

Single list loose with multiple paragraphs in an item:

- How you doin'?

- this item contains multiple paragraphs.

  More than one that is.

  Three to be exact.

- And this one is just a bunch of lines. Spliced together as a single item. A single paragraph.

A single list that looks like multiple lists separated by a blank line:

- list 1
- with three

- elements

- still list 1

- adding four
- more

- elements

- sic, this is still list 1

- now with
- even
- more
- elements

There's no way to actually get multiple consecutive lists in Markdown. Neither Markdown.pl nor python-markdown allow it either. In a mailing list thread a few years back, John Gruber suggested using double blank lines to separate consecutive lists but no implementation does it. For now you need to separate consecutive lists with unindented text:

- list 1
- with three
- elements

Cough.

- list 2
- with
- four
- elements

Cough. Cough.

- list 3
- with
- even
- more
- elements