F(2), F(3), F(4), F(5), F(6), F(7)
Start with one (an order 1 mobile).
Add one to make 2 (an order 2 mobile).
Add one more to make 3 (an order 3 mobile).
Add two more to make 5 (an order 5 mobile).
Add three more to make 8 (an order 8...).
Add five more to make 13 (an order 13 mobile).
Use whatever shapes or articles (school mascots maybe) for your mobile. Vary the length of the strings if you want. The markings on the bars indicate the balancing points (approximately).