Minecraft – Making Command blocks send redstone currents upon player death

There is this one character (I don't know what it is yet, either), that sometimes, somehow, makes its way into commands. Try going to the beginning of your /testfor command, and holding -> until you reach the end. There may be a spot where your cursor stops moving, and there should be a zero-width invisible character there. It shows up in regular editing software, I always check if my commands aren't working.

Ok, after some (5-10hrs) work I got a solution:

Now, what the numbered parts are:

1. Button switch - one button press is like a lever switch
2. Fast Redstone clock (minimal repeater delay)
3. Piston that turns the system on; the repeater is essential, otherwise the piston will go on-off-on on button press
4. Command blocks, each part has these four commands:

/execute @a[ry=112,rym=-112] ~ ~ ~ fill ~ ~ ~+1 ~ ~+1 ~+1 minecraft:barrier 0 replace minecraft:air

/execute @a[ry=22,rym=157] ~ ~ ~ fill ~+1 ~ ~ ~+1 ~+1 ~ minecraft:barrier 0 replace minecraft:air

/execute @a[ry=-67,rym=68] ~ ~ ~ fill ~ ~ ~-1 ~ ~+1 ~-1 minecraft:barrier 0 replace minecraft:air

/execute @a[ry=-158,rym=-22] ~ ~ ~ fill ~-1 ~ ~ ~-1 ~+1 ~ minecraft:barrier 0 replace minecraft:air

5. Finally, this last Command Block resets the whole cycle:

/execute @a ~ ~ ~ fill ~-5 ~-2 ~-5 ~+5 ~+2 ~+5 minecraft:air 0 replace minecraft:barrier 0

Notes:

• all repeaters must be set to minimum delay
• the lower #4 command blocks are not connected with a repeater, the upper ones are.
• all the Pistons are Sticky Pistons
• the system will not delete the remaining Barrier blocks when turned off; It's better to use this:

• I recommend to use "minecraft:stained_glass 4" instead of "minecraft:barrier 0", if the player breaks it, a new glass block appears almost instantly.
• It's convertable to use the 1.9 chain command block feature, but I don't recommend it because of different repeat frequency.
• The system is reliable - you can't move forwards whatever you try.
• Even if you are falling/flying upwards/sprinting/potion sped up, the barrier block(s) farther from you will be deleted.
• You can try it yourself and use/test/edit it! - let's say, it could look like this:

The Command block next to the Button has this inside:

/clone XYZLeftChest XYZLeftChest XYZWool

The other two new Command blocks reset the cycle:

/setblock XYZChestUnderHopper minecraft:chest

/setblock XYZWool minecraft:air

Inside the left Chest place some items for signal length.