They've been doing a lot of web promotion as well as on-network advertising. I haven't seen any subway "take overs" like we were treated to for last year's "Make 'Em Laugh".
Here's a pencil test from the final of segment of the film. It's the first pencil test, no inbetweens, rough camera, et cetera.
It goes to show, in part, how reading a pencil is skill developed over years of screening. The viewer needs to understand what they're looking at and imagine what's missing. Once you've done that -you can truly appreciate the work of an animator.
Doug Compton animated this segment.
PBS has not yet uploaded this in color, but you can see other clips (in incredibly low quality) here.
The final animation is actually pretty different from this first pencil test. Typically you don't want to/can't afford to rework animation, so most narrative decisions are made in the storyboard.
Here, we wound up changing the elephant, eliminating a scene or two and bridging the gaps with additional animation. Liesje Kraai did most of that re-working.
The final scene of the film, not included in this test, was a camera move animated by Elliot Cowan after Marina Dominis' detailed background art.