Online Chess Analysis

Is there an online tool where one can paste a FEN or just set up the pieces (say at the middle game or endgame), then let the engine play it out til mate (or draw)? Preferably, it would be nice if the tool would analyze and play out, show alternate lines, and allow manual input of annotations (or even self-annotate).

LOL. Don't hold back. Tell us how you feel.

I'm referring to the case where I have, say, a puzzle. I want to be able to do what MeTristan did in the 7/16/2014 daily puzzle:

http://www.chess.com/forum/view/daily-puzzles/7162014---mate-in-4

8

7

6

5

4

3

2

1

a

b

c

d

e

f

g

h

Note the quick mate, with alternate lines showing longer mates. He was also able to annotate and add in his own comments. OK, that didn't paste right (I don't know how to post correctly -- I just copied and pasted the board and moves with annotations -- that would be my second question), but you see the annotations.

As far as I can tell (could be wrong on this), the only way to do that with Chessbase is to buy and install software (not an option for me since I have an old Mac that Chessbase and other programs won't run on). I don't see that capability on the online versions of Chessbase.

There must be something online where you can analzye puzzles and have it play out, with the capability to add alternate lines of play. The closest I have found is the following:

http://analyse.deep-chess.de/

However, it doesn't seem to allow for analyzing alternate lines of play (or at least I can't figure out how to).