How does this thing work?

Working out how exactly Grandads pianola works. Bearing in mind Ed always thought it was an ordinary piano and had no idea of the music that could come from just pumping a couple of pedals. She did discover, that 'just pumping a couple of pedals' is an inaccurate description of the effort required to get the pianola going!

We sang along to a few numbers, including Yellow Submarine and Bring me Sunshine, before Nige collapsed exhausted over the keys.