Get Squiggling

Series about Squiglet, a monster who populates his plain white world using a magic crayon. Squiglet draws a laughing hyena called Harry. Harry's serious friend Horace the warthog is coming for tea, and Harry wants to stop laughing all the time. Harry and Squiglet hear someone playing a beautifully sad tune on a violin. So Squiglet draws Harry a violin of his own, but Harry can only play happy tunes. Perhaps the Squiggle Pad will provide another clue.