Nekonote Escape 05 - X'mas

[Mistery]

So far got

key (used), Santa hat (used), kind of an equation, a red 3, =5, plugged in Christmas tree and seen colors on it

EDIT

thread (used), seen shape clue for code, got white rectangle thingy

Still missing 2 numbers for the safe.

Oh, got now

hint from frog

Now missing only 1 number of code.

EDIT
Opened safe
Hmmm, where to use that new item?

[Mistery]

This is the next room escape game by the creator of the Nekonote series.
Gather and use items in order to escape. Good luck

Play Here

Please use spoilers to give hints:
[spoiler=Title Here]Enter text here...[/spoiler]

Do not post a full walkthrough until December 25.