Very impressive! The third one is my favorite by far. I love drawings that are taken from a different angle. I have a flickr account and just came across a drawing someone did from the knees down on a horse. It's neat how everyone has different perpsectives and use it in their art. It's what makes us all so unique as artists.
So there's another wonderfully talented artist on the board to admire. Amazing work =)
The aim of art is to represent not the outward appearance of things, but their inward significance. ~Aristotle