Climbing the Wall

Ok,
here's my latest take on a teaching analogy. The school term is climbing wall. One of those indoor synthetic places with all the little plastic holds which can be used to make it up to the top. Those holds are the students. Some are large easy to reach and hold onto, others are thin slivers and can barely hold your weight, hurt your fingers to grip, and are always just a little too far out of reach to be really comfortable.
So you start the term at the bottom of the wall and you need to make it to the top, the end of the term. As for those holds, well in climbing you don't necessarily need to use all of the holds to make it to the top, and the students? Well maybe you don't reach all those students in the course of a term, you reach the easy ones, you get as good a grip as you can on the tough ones, and perhaps there are just some that are out of reach.

So does it work? Or perhaps it's late-year-tired-rookie thinking. Let me know.