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Ok, here's another one.

As represented in the visual, I have a redstone torch attached to a block, that is, a redstone lamp. But as represented in the visual, by my extraordinary drawing, the redstone torch actually exist in the block which's borders shown by red. Since my redstone lamp is next to this block which is represented by red borders, it must be switched on and hence light up. But it does not. Why?

Thanks in advance with most appreciation.

P.S.: We know that the block shown by red borders is powered because of the second visual.enter image description here

enter image description here

enter image description here

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    Freehand circles...I mean cubes? xD – Linuxmint Dec 7 '13 at 19:17
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A Redstone Torch only powers all other blocks, except the block it's on.
(As long it is placed on a block, and the torch is sideways.) enter image description here

There is no way to light the lamp with the torch in that position, due to the torches properties: enter image description here

It will merely loop, then burn out.

Source: http://minecraft.gamepedia.com/Redstone_Torch and presonal experince.

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  • Well, thanks but I think that you haven't read the question properly. What I state is that the redstone lamp that the redstone torch is attached on should light up, because of the block that redstone torch is in, that is the block shown by red borders. – Utku Dec 7 '13 at 15:45
  • @Utku I do answer your question; the first few sentences explain why it doesn't work. – RavenM Dec 7 '13 at 16:58
  • You don't, my friend because I'm not trying to power the block that the redstone torch is on. I'm stating that the block that redstone torch is on should light up, simply because the block the redstone torch is on is next to a powered block, that is the block the redstone torch is in, which is the block shown by red borders. In other words, the redstone lamp which the redstone torch is on should light up because the adjacent block to it, shown by red borders is powered, by the property of a redstone torch. Hope it is more clear for you now. – Utku Dec 7 '13 at 18:06
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    And understanding the question, if this is an exceptional condition, you should state why there is such an exception for it. – Utku Dec 7 '13 at 18:08
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    The block the redstone-torch occupies (the one you outlined in red) is, in fact, not powered. A torch is a transparent block, and thus can not be powered. The torch in turn powers all adjacent blocks, except the one the torch is attached; this is just how redstone works. If the block the torch is attached to would be powered too, the main mechanic of unpowering a torch by powering the block it is attached to won't work (namely: inverters, redstone towers, nearly every circuit). So, @RavenM's does answer your question with his first sentence. – Pit Dec 7 '13 at 20:57
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(I'm adding the information I posted in the comments to RavenM's answer as a separate answer, just because the 500 character limit and the visuals get a bit crammed.)

P.S.: We know that the block shown by red borders is powered because of the second visual.

This is a false assumption. The block the redstone torch resides in is in fact not powered. It is not possible that this block is powered, as the torch is a transparent block, and transparent blocks can not be powered.

Source for this statement can be found in several places in the Minecraft wiki, I'll quote two instances:

What you have to realize is, is that the torch powers all adjacent blocks to it's position, except the one it is attached to, and the one it occupies (given the reason above).

[...] is the fact that the block that redstone torch is attached to being not powered an exception? If it is an exception, in which source is it stated and why there is such an exception?

Yes, you could say that this is an exception. Regarding a source, I haven't actually found one. As this behavior was in the game since Alpha 1.0.1 and has not changed since, I believe this gets seen as common knowledge and just isn't documented.

As for why, I already mentioned that if the block the torch is attached to would get powered as well, one of the main mechanics in redstone -- powering the block the torch is attached to to turn it off -- would no longer work.

Think about it. Attaching the torch to a block would power the block, would turn off the torch, would unpower the block, would turn on the torch, would power the block, ...

You would have to get rid of this mechanic to still be able to use the redstone torches if you made that change.


Powered blocks

You mentioned the fact, that blocks can be in four different power states:

  1. Level 0 power: Unpowered (shown as blue wool/carpet/glass)
  2. Level 1 power: Powered, emitting no power (yellow)
  3. Level 2 power: Powered, emitting second degree power (orange)
  4. Level 3 power: Powered, emitting first degree power (red)

To clarify the different states, we'll go over a few screenshots.

Power states, redstone output

(As already mentioned, the four power states are visualized with four different colors.) This shows, how you can achieve the different power levels, and how they interact with adjacent redstone.

Starting from the right, we have the red wool, which gets powered by a repeater, thus emitting first degree power. First degree power means, that adjacent redstone gets powered by the block, so it lights up the redstone dust.

The orange wool gets powered by a redstone wire facing into the block, causing it to emit second degree power itself. Second degree power does not power redstone dust, but it powers repeaters, lamps, pistons and redstone torches (and probably others). See the following image for demonstration.

Second degree power, powering outputs

Next up is yellow: Powered, but not emitting power. I guess it's pretty self-explanatory, still, see the following picture for more information.

Powered block, not emitting power

The last one, no power (blue), is also self-explanatory.

Now, coming back to the torch, the following picture shows the different power states the blocks surrounding the torch are in:

Blocks surrounding torch

As you can see, the block above the torch gets powered, emitting first degree power itself (see picture).

Torch powering block to level 4

The other blocks surrounding the torch, except the one it is attached to, get powered, but they do not emit power themselves. You can see that this is true in the following two pictures.

Proofing power level 1 Proofing power level 1

The last block -- the one the torch is attached to -- is unpowered. Proof for this is found in the first picture of your question.

Conclusion

Given that a redstone torch is not affected if it is attached to a level 1 powered block, one could argue, that the torch itself should power the block it is attached to with level 1 power. This would make it easy to power a redstone lamp -- without powering the lamp itself to power level 3 as a lever would do.

If this would be useful or not -- I don't know. But changing the mechanic might cause problems in redstone circuits I didn't think of here.

Also, I think that if the torch powered the block it is attached to, it would be even more confusing for new-comers than the other way round, but this is just a personal guess.

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  • (1)Finally an acceptable answer. Though still I'm not fully satisfied, this clarifies some things but creates new questions. Because as far as I understood, there are 4 types of redstone powering in the blocks, which are: 1) Powering a block so that it will activate the adjacent redstone devices and light up adjacent wire. 2) Same with 1, but the adjacent wire will not light up. 3) A block that is "switched on", meaning that if there is a redstone device in that, it will activate. These are adjacent blocks of powered blocks. 4) No power relation at all. – Utku Dec 8 '13 at 10:52
  • (2)According to these definitions, by experiment, a redstone torch will "switch on" adjacent blocks, except the block that it is attached to. But according to these definitions, there is no problem with a redstone torch "switching on" the block that it is attached to, since that block will not be a powered block and hence will not turn off the redstone torch. This is the part that confuses me, whether these definitions are true or false. – Utku Dec 8 '13 at 10:52
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    I expanded my answer by a good amount, explaining power-levels in more detail. If something is not clear, just keep asking! – Pit Dec 8 '13 at 12:04
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    What's going on with the right most yellow block? The side is a redstone lamp, and the top is yellow wool? [Fabulous answer!!] – John Dec 9 '13 at 15:27
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    Yes. I covered the lamp with yellow carpet, to show that (a) that a lamp get's powered in this position, and (b) to still have the color as a reference. – Pit Dec 10 '13 at 20:46

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