Revealed alphabet blocks + Help for the piano puzzle (Spoiler Inside!)

This guide is for those who don't have the patience to solve the letter puzzle in section 4 of this game.
It is clear that this guide is full of spoilers, so don't blame me for that.

Letter Blocks

For those who don't want to puzzle along here are the revealed blocks:



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There is one block in the library which represents the letter "Z".
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See the screenshot in the next section for the one block in the piano room (which is a "P")

Help for the piano puzzle

The piano puzzle might be tricky if you're not a piano player. The game helps you with that as you can find a music sheet right-hand side to the entrance. Plus you can pick up a colored music sheet in the children's room inside the lowest drawer.
Anyway, that puzzle is purely optional for completing the game and your reward will be a picture with a kid playing piano which you can't pick up.



Reward:

[GrayFox]

No "X" block?

[deltaPrime]

The 'Q' block is in picture 5, to the right of the bookshelf. Took me forever to find.

[sjs.stever]

Is there no "Q" block? I figured out what symbol should be Q but could not locate the block itself...

[ReverendTed]

Ah, thanks for the guide! I thought I hadn't completed the piano puzzle, but I'd already revealed the "reward". I hadn't noticed you could put the sheet music on the stand, though.