Got it, thx Grumm
@CubeTheThird (or however you reply to a specific person) The redstone SHOULD behave like this: The redstone block powers the command block, the command block destroys the redstone block to create another one on and on. When the redstone block is pushed aside, it should stop the command block from creating ANOTHER redstone block to continue the loop but it just keeps going.
Oh whoops sorry 😛
P.S. The video in my edit is unmodded.
And isn't unmodded Minecraft called "vanilla"?
It does happen in vanilla. (unmodded Minecraft)
I tried and it also happens in 1.8.1 vanilla.
Edit: Optifine is a mod that allows you to have better fps, it doesn't change any game mechanics.
Here is a video of me doing this glitch in vanilla:
http://youtu.be/NWhMLcH4IMU
Switching the commands of the two command blocks should not make a difference, but it did. One lets the player emit a redstone signal, the other leaving a trail of redstone blocks behind.