How to draw an idea?

I was working on a pretty personal project this week, and for one of the pieces I was trying to illustrate an idea as an idea, experimenting with using the image of a horse as a visual metaphor. I find them really difficult to draw--I never was much of a horse girl, though I did try to pose as one by choosing horse wallpaper when we redecorated my room in third grade (which stayed up, unfortunately, until tenth). The difficulty in rendering them for me has become sort of the point of the piece, along with the fact that as creatures they embody all these relevant characteristics: they're hulking and fast yet easily spooked and fragile; they were and in some contexts still are our vehicles and our engines.

I find it much easier to draw if I put some blobs down first, and I quite like how these sketches turned out.  But the project was killed, so for now they're experiments and future reference, should I decide to finish this on my own.