This could be interesting for you:

LoadSaveBlock(62831);
This can create a short beam of light with super speed!

But dont ask me how this works!

I just know that if glas is full of light sometimes it accelerates the light when it comes out of the glas.
And because that its not happening everytime when a photon is leaving the glass I thought to "store" the fast photons and release them with opening a wall..

It's also interesting when you pause the simulation after you released a beam. Then you can save this light beam as a stamp.

If you try this new stamp you will get white photons with a higher speed than normal photons (But slower than the super speed light beam)