I thought it was a split frame thing too, but then noticed that they veer into the tens place pretty frequently and cast shadows. :) (And the other comments give more details about the original art installation.)
That's not to say that you couldn't do a split-frame thing like this, with a little bit of cleverness and planning. Even if it were only split around the middle, that's only 72 transitions to film, which isn't too bad.
That's not to say that you couldn't do a split-frame thing like this, with a little bit of cleverness and planning. Even if it were only split around the middle, that's only 72 transitions to film, which isn't too bad.