Room B4 (1) "Perpendicularity"

Notice that, unlike the previous two rooms, the two receivers aren't on opposite walls.

How do you think that might affect what you need to do?

Both receivers have timers again, so you'll need to split the particle to activate them both simultaneously.

If you split it in opposite directions like before, though, you'll find that you can only get one particle to a receiver whilst the other one turns the wrong way.

Don't forget you can press X to reset the room or R to load the last checkpoint if you need to.

Seeing as the receivers are on perpendicular walls, try splitting the particle so the resultant pair are also perpendicular.

There are two ways you can do this with the given arrows - up and left or down and left. Experiment to see which combination is most fruitful.

Combine the up and left arrows. The down arrow should then turn both particles towards their respective receivers.

Careful placement of the combined arrows will ensure both particles enter the receivers at exactly the same time (though this isn't strictly necessary).