The full changelog is listed on Mojang's website (copied below).
The line you mention, "Added a few other things for players to discover," is in the Tutorial World section. Therefore I suspect it just means they added some cool touches to the tutorial world to demonstrate the use of new items (pistons, stacked fences, etc), to add to its charm. They may have added some little easter eggs to this world too, but I can't say for sure.
Minecraft: XBox 360 Edition July 2012 Update Changelog:
http://www.mojang.com/2012/07/minecraft-xbox-360-edition-update-is-out/
Features:
- Added Pistons & Sticky Pistons.
- Added Stackable fences.
- Added Shears – required to get wool from sheep, and to collect leaf blocks.
- TNT needs Flint and Steel or Redstone to detonate.
- Redstone wire will now connect to a repeater.
- New textures for Cobblestone and Brick.
- Added Character Skin Selector to allow players to choose their skin from the default skins, or from Downloadable Content skin packs.
- Added lighting improvements (brought forward from 1.8.2 update) and snow & rain improvements.
- Added a save file cache to improve the speed of displaying the saves list.
- Added ban list functionality to allow players to self-ban from levels they feel contain offensive content.
- Added a ban list section to the How To Play menus.
- Added an option for the host to limit online games to only players in their friends list (no friends of friends).
- Added a seed display to the level load screen (requires existing levels to be saved out again to add the display).
- Changed the tooltip display setting to in-game tooltip display, so that tooltips always display in menus.
- Added the crosshair to the list of things affected by the opacity slider.
- On using the quickselect bar, the opacity of the quickselect, tooltips, splitscreen gamertag display, and crosshair will be set to
80, and will fade back down to the user opacity setting after 6
seconds of no quickselect bar use.
- Added some more Tips & Trivia to the loading/saving screen display.
Tutorial World changes & additions:
- Added optional tutorial for Pistons and Redstone.
- Added a self-building bridge to the castle using Pistons.
- Added some sugar cane, cactii and clay to the world.
- Added a few other things for players to discover.
Fixes:
- Fix for only the host being shown the pop-up when any player attempts to place lava near the spawn point.
- Fixed tooltip for Flint and Steel.
- Fix for Note blocks not showing notes.
- Fix for Leaderboard reads taking too long.
- Fix to block players re-entering a level they have been kicked from, until the level is restarted.
- Fix to stop players being able to join a game when they are not a friend of any player in the game.
- Fix for Netherracks re-appearing after being mined.
- Fix for a rare crash on entering the Nether.
- Fix for attacking enemies at a different level not damaging them.
- Fixed a problem causing some save games not to load.
- Removed Herobrine.
The reason why it stops working is the repeater happens to lock the other repeater when it is powered. Chances are that design was not made to be spammed. A solution I'd suggest is make a fill clock (if you want your construct to be activated every tick all the time) or if you want it to pulse when ever you flick the lever (just like the pulse generator you where using) you can use the second design I listed.
(note: all screenshots are in 1.9 but everything listed will work in 1.8)
Design 1: The Fill Clock.
This is when you have 2 commandblocks running a fill command twice every tick, and looks something like this.
![enter image description here](https://i.stack.imgur.com/n5HPB.png)
The commands the command blocks are running (from top down) are
/fill ~ ~-1 ~5 ~ ~-1 ~ redstone_block
/fill ~ ~1 ~5 ~ ~1 ~ stone
How it works is the top commandblock is run after the bottom commandblock. So the area get filled with stone (unpowering all commandblocks along the blocks) and then instantly replaced with redstone blocks re-powering them all.
Design 2:
So this design uses the same principal as design 1. It will power what you want for 1 tick, and it looks like this.
![enter image description here](https://i.stack.imgur.com/d48RC.png)
From the top to bottom the commands are
/setblock 297 91 983 minecraft:stone
/setblock 297 91 983 minecraft:redstone_block
The commandblock to the right has the command /say hi
just to prove that the stone block beside it (the block the /setblock
targets) does it powered for 1 tick. and it looks like this
![enter image description here](https://i.stack.imgur.com/u8KKC.png)
Hopes this helps!
Best Answer
What you actually want is a clock circuit. The simplest is a repeater, a block of any kind, three pieces of redstone, and one redstone torch, arranged like so:
The torch should be attached to the side of the block, and the repeater powering into the adjacent side of the block and (to avoid burning out the torch) set to 2 ticks or more.
This will give you a stable clock signal that you can pull from almost any part of the circuit. You can easily add an on/off switch on top of the block to stop and restart the cycle.