i found it very confusing that the introduction at each level links to the next level but does not tell you to try the exercises. i didn't even realize that the tabs were exercises per level as i consider tabs a higher level hierarchy compared to the previous/next buttons. (i expect those to work within a tab, and not switch to a different row of tabs)

and also, why introduce an echo command in level 1 only to drop it in level 2? they could have waited and introduced ask in level 2 or 3 even.

i love the quiz questions though, they even make me, as an experienced programmer, think