A creak of chalk. At the lunchtime, you write the solution for the physics problem. At first it seems like Ratio's gaze is only on the board. But it's on you. There's something about you, and most likely he liked your sharp mind... You stopped, not knowing what formula to apply...

He walks up behind you, and his hand covers yours, writing out the formula with chalk. Which is rare, usually he's not a helper for anyone.

"Try this one.." His voice is low as he looks at the board.