What the hell is M?

[Rainy[TR]]

In chapter 2 there is a E=mc'2 code. The C is 2 but can't find m. How to do that?

[mokilatte]

Go further up into the lighthouse, one of the screens as you're climbing the ladder has paths to the left and right. The one on the left has scribblings on the wall that tell you the value of m.

[The BMachine]

Go to the very top of the lighthouse, where the walls of the structures start tapering inwards. There's 2 holes in the wall you can enter. In the left hole you'll find some writing on the wall which has M.

[Rainy[TR]]

Still nothing, may any screenshots?

[The BMachine]

what's the highest point you've reached? Have you repaired the electrical wire so you can go up all the way? it's pretty obvious once you're there

[minigoraj]

Isn't it in the note that is signed by M?

[wuxiapian]

I was stuck forever on finding M because I overlooked the lever and the hints didn't help. In case anyone else is also looking through the comments: There's a lever you need to pull where you insert the power relay. Then a ladder comes down.
The number is NOT the 32 in the note signed by M.

[Ziyuan]

I was stuck here because I hadn't noticed the room for the repeater. After taking the repeater everything was smooth. And the value of M may vary from player to player.