Oh dear.........remember the first lesson on drawing the horse head?  As I am adding my eye and the nose, I see that this head is not right.  I do fine if I'm just drawing the horse head, but somehow, putting the head on the whole horse throws me off.
 
 

I fix it without too much trouble.  Using the Freehand Select tool, I select  the head from about halfway down.  Then cut and paste as a new selection, moving it up as I place it.  Then I just correct any stray draw lines.  Ok, that looks better!
 
 

Now for that darn rear end!  Since the rest of the horse is fine, I go ahead and delete 3 of the vector layers.  I leave my rear circle just in case.  From the first image to the second, I had restructured the rear legs to be next to each other and to have less top area on the front leg.  But things still looked off.  That's when I selected the rump and the tail.  Cut and paste as a new selection, and moved that part more to the right, closer to the neck.  The horse was too elongated!  Once I had the correct length of the horse, and I had the front rear leg right, the rest was easy.  I did the same thing here that I did with the front legs.

I start the second rear leg to the right of the the ending point of the front rear leg.  I first start out with a narrow space between them, then I make the space equal the rest of the way down.  So actually, you need to just get two legs to look good for the horse.

A little cleanup work leaves me with an image that pretty much looks like a horse!  This is also not ready for stained glass, but you get the idea.  You can make a unicorn by adding a horn.  Use the Straight Line brush on the Draw tool.  If you want a Pegasus, have the mane fall down on the neck and add wings where the mane is flowing out from this horse.