How about a simple checksum? For example, append -Sum(list) to the end, then when loading you can check whether the sum is zero (or with some tolerance, if necessary)

It will probably keep happening. The ones who do it also aren't the ones reading this thread.

INTJ is pretty rare, but polls on other programmer websites have shown that it's very common among programmers.

Chapter 5 - Area 3

There is a moving portal in Portal 2, and you can set a var in Portal 1 to make it possible in custom maps. The game reacts to this situation by not letting the cube through.

Say the yellow portal is moving at speed v (relative to the ground and therefore the cube). When the cube is starting to go through, the part that comes out the blue portal must have speed v (at an angle and upwards though) because that's the speed at which it is being pushed through.
The cube has speed and therefore momentum.

Ok, what do you guys think about this

(spoiler alert: if you try this in the game, the cube refuses to go through at all)

I'm going for B, because:
1) Option A implies the cube keeps whatever momentum the cube had in relation to the "ground". That means that:
1a) if you take a cube and a portal on a fast train and then slowly push the cube through, it comes shooting out the other side at high speed. Ok, then what happens when the cube is halfway through? The back end is moving into the portal at a slower rate than the front end is leaving the exit portal. So the cube is ripped apart.
1b) in the setup in the picture, the front half would not be moving at all, so it wouldn't actually be going through at all. Of course that means you couldn't have stuck in the front half either.
2) the cube has a relative velocity with the entry portal, it must have the same relative velocity with the exit portal
3) the argument that throwing a portal over an object is like throwing a hoop over it isn't really true - a hoop has the "exit" moving at the same speed as the "entry", and indeed the cube "exits" with the same relative velocity as it enters, and that leaves the cube stationary just as it would if the blue portal was pointed upwards and falling at the same speed as the yellow portal is falling (in that case the cube would move through space but gain no momentum).
4) from the perspective of the yellow portal (and choosing an other inertial reference frame like that is OK), the cube is moving and some speed and it will keep that speed at the other side.

Thoughts?

Here are some, format is mask (hex), solution (hex), hardness, timestamp.
The levels are a better indication of how hard they are, but within a level the hardness is relevant.
level 1
level 2
level 3
level 4
level 5
level 6

Well as you may know I made this, so if you need any help.. (with, say, a ton of 8x8 puzzles, so you don't have to rip that site)