Friends of mine are expecting a baby soon. I thought I'd make them a mobile. I'd seen Gobbi Mobiles when Goblin was a baby and thought they were lovely, but pricey. But I read a basic tutorial on Art Club Blog about how to make felt balls, and decided I could do a DIY job.
The Gobbi mobile is part of the Montessori Visual Mobile series. You can read more about the series at At Home with Montessori who describe the Gobbi as "The third mobile in the Visual Mobile Series, the Gobbi Mobile is a set of small spheres in graded shades of one colour. This mobile is presented to infants between 7 and 10 weeks old. It represents a further step in the development of the child's visual sense, in which she can now perceive more subtle variations in colour. The mobile is named for Gianna Gobbi, an Assistant to Infancy trained by Maria Montessori."
The balls are normally in a straight line, but I used a bit of artistic licence to hang them in a spiral. When the mobile spins it will look like they are moving up and down.