Why does my friend's skill tree look different to mine?

[Surubi]

My friend and I started to learn german around the same time, but when I click on their profile, their skill tree is in a different order to mine? For example, for me, animals was the 5th lesson I had, but for them, animals is the 8th. They have a module called 'Masc. Fem.', and I don't seem to have that at all!

What's going on?

[Lenkvist]

Duolingo is testing a new version of the skill tree. For more info:

http://duolingo.com/#/comment/180620