Saw something curious in Figure 17 yesterday.

Tsubasa and Hikaru are told by their teacher to practice by sounding off a line of vovels: "A,e,i,u,e,o,a,o".

The sequence is not random, it can be found around the net. Google was entirely useless, even with double-quote. It was able to find Chinese blogs only. Yahoo easily found Japanese entries and this posting by member "crabity" on OutpostNine (the old home of Azrael):

I was also wondering if people still practice by saying that rhyme...it's a good way to practice your mouth shapes.

a e i u e o a o
ka ke ki ku ke ko ka ko
etc....

Yahoo. It's better.

UPDATE: Someone adds Hitohira to the list. I neglected to mention that Tsubasa and Hikaru were preparing to a stage play as well. The excercise wasn't a part of class activities. The discussion at forum hints that it could be, but in Figure 17 it's not.

UPDATE 2007/12/06: Shingu has it too:

It's in ep.19 or about that.