Hi Lucinda,
Good eye! This is only two slides. The first is an intro and the sushi selector, and then a second slide has the sushi tray. I like to use music in my demos and the only way to get the music to feel seamless is to figure out a way to put things on as few slides as possible.
Below is a link to the download if you want to see behind the curtain. Michael Hinze helped me with the sushi tray on slide two. I couldn't figure out how to get the effect I wanted so I posted the download in the Articulate community and he solved the issue for me. He used javascript to set positions for the chosen sushi. I can't even explain how he did it!
https://jodichallenges.s3.amazonaws.com/287+Interactive+Sushi+Table.story