Shark Tooth Ache

This is Arthur's shark, a favourite Christmas present, but with a problem. It was not travelling in a straight line as one of the drive wheels was sticking. So it was handed to grandpa to fix. 

I pulled it apart, tried to understand what did what and how, and eventually tested it and then tried to put it back together. That was the longest part of the job. The second longest part was looking for a stray screw that fell and bounced. Grr.

The shark is now working, which will please Arthur, but not his younger sister who is afraid of the chomping mouth as it speeds around the floor. In spite of this dislike, she has been seen feeding the shark when it is at rest.