Ear-Training

I used to have a composition/theory professor who loved to give us little what he called "ear-training" tests. These were nothing like the usual ear-training tests where you had to take a chorale down in dictation or sing a melody at sight. No, his idea was to play us a really unusual piece of music and watch our reactions to it. The pianists were particularly troubled by a piece like this:

Of course, he didn't tell us what he was going to play. It is simply not possible to actually play that on piano. The composer, Conlon Nancarrow, manually cut holes in piano rolls to create a kind of non-electronic, electronic music. Here is another sample:

Half the students were asking themselves "why is the music never changing" while the other half were thinking "listen to those interesting changes". Here is another sample:

Scroll ahead to anywhere in the middle and ask yourself these two questions:

1. What is the meter?
2. Where is the downbeat?

One more? Ok, what is going on in this piece?