Your tree of thoughts
Everything you learn on Why Tho? grows your tree of thoughts: a trunk of maths and science skills, and your own branches for everything else you're curious about, from history to cooking.
See what you know
The tree is drawn like a real tree that you can tap and zoom into. Skills you've learned glow; the rewards you earn hang on it.
Trunk and branches
The trunk follows the maths and science learners meet from about age 13. Everything else you learn grows on interest branches, so a question about the printing press or recipes has a home too.
A small icon that grows
In the top bar, a little tree icon grows as you learn. Tap it to open the whole tree.