The latest Spiffing Brit is on a Minecraft exploit and it's amusingly simple in how it works: You have a friend ride a donkey and disconnect.

The less tl;dr exploit explanation:
you put a chest on a donkey, which is an accessible mobile inventory.
you then have a friend ride the donkey, you put items in the inventory of the donkey, and then you have the inventory open while they disconnect.

then you take the items back out, they connect, and WHOOPS now the donkey still has the items.

And it happens because of the weird way that Minecraft handles "vehicles" like donkeys, horses, and boats.

I guess because it doesn't want you to be on a boat and then log out and come back to no boat, you actually take the vehicle with you when you log out

so if you're on a horse and log out, the horse vanishes, and it's temporarily stored in your player file instead of the world file.

and then this exploit apparently happens because minecraft doesn't close your inventory access (or notice you removed from an inventory that logged out) when the donkey gets yoinked into the player-file because they logged out

presumably because the player is withdrawing items from the inventory-in-the-world and not the inventory-in-the-player, it thinks that it's completely valid, and you get items back, but then when the donkey reappears those items are still there, in the donkey.

so WHOOPS INFINITE DUPLICATION GLITCH

This isn't the first time they've done Minecraft, and I like this exploit the best:

the tl;dr is that minecraft has a limit to how much metadata can be saved to disk inside a chunk (a 16x16 piece of the world), and if it's exceed, the chunk simply doesn't save.

so you can exploit it by cramming TOO MUCH INFORMATION into an area to exceed the maximum information density of the world.

which is some sci-fi "we live in a simulation and we're trying to hack the matrix" bullshit.

but the basic trick to turn this weirdness into an exploit is that you put an item in a chest in a chunk, then you overflow the information limit while removing the item.
So now the game thinks the item is on your player, or in some other chunk.

but since that first chunk cannot be saved, it cannot overwrite the version which has the item with the has-no-item-and-has-overflowed-information version.

So the first version remains in memory.

you then just trigger the game to reload that chunk (by logging out or getting too far from it) and now it reverts back to the first version, which has the item being duplicated in it, again.

it's a perfectly normal case of putting too much information into an area to cause it to desync from the timestream so you can make non-local changes and end up breaking physics.

PERFECTLY NORMAL THING TO DO IN THE VIRTUAL LEGO GAME

I remember being a kid and playing with my legos and my mom came in and was like FOONE ARE YOU TRYING TO BYPASS THE BEKENSTEIN BOUND OF THE UNIVERSE AND CREATE A BLACK HOLE IN YOUR LEGOBOX?

and I had to be "no, mom, I'm building a space ship"

jokes on her: it was a faster-than-light spaceship.

and according to relativity, going faster than light is equivalent to going backwards in time...

and depending on how paradoxes work with time travel, you can use it to duplicate items.

how? simple.
I take a diamond and put it in a box at 1pm.
At 2pm, I take it out, and put it in my pocket.
I then set my time machine to 1:59pm, and take the diamond out of the box a minute early.

and then I check my pocket.
Do I still have a diamond in my pocket, as well as the one in my hand that I just picked up? Possibly!

Or maybe the time travel paradoxes just made the universe explode.

in any case, if it worked, I can now just set my time machine back to 1:58 and pick up another copy of the diamond.

Don't ask what happens if you go back to 1:57, open the box with the diamond in it, and put in a diamond.