When I was in jr. high, we were given a knife and a bar of soap to carve (seems a bit devil-may-care on the teacher's part now that I think about it). I had such grand plans to carve an exquisite horse (or unicorn or pegasus) and I just ended up with smaller chunks of soap... That was such a great lesson for me and I still think of it often when I draw. I rarely get things to turn out on paper the exact way I hope they will and I am ok with it.
What I am trying to say is that if you try to draw a real gnu and end up with something that looks like this; it's all good.