Map sp_a1_bts_wind features a conveyor belt which drops "surplus" Cubes into a giant shredder. You are supposed to take one from it to progress the story, but there is nothing stopping you from taking more than one, except that after certain amount, which is 15 (I have not checked this, but that is the amount I was able to get), the game will stop spawning them and will reward you with a secret achieviment.

It is natural for some players to seek for opportunities to use them to get to some places they are not supposed to be. And, in case of that particular map, you can get pretty far with what you got.

First, get as many cubes off the conveyor as you can; you will need at least 8 cubes, but it will be much more convinient to have 11 or more. One of them is to progress the story, and rest are left for you to play with. The first and most obvious thing to do with them is to get on the roof of the control room.

You have to sacrifice one of the cubes to shut down the fans; otherwise, the wind will constantly push the cubes when you don't hold them.
After that, build a staircase in front of the control room entrance; it has to be at least 4 cubes high. Here's mine, consisting of 10 cubes:


From the fourth cube of height you can jump on invisible wall above catwalk fencing, and from it (using crouchjump) on the roof of the control room:


Bring at least 5 cubes on top of control room. You can dismantle your staircase from it's top; you won't need for the rest of climb, just retain access to the roof until you done with cubes hauling.

Your next goal is to get on top of the blue beam directly over the top of the control room. Put a cube next to it, and another on top of the first slightly off center to form a small ledge you can step on. From second cube, crouchjump onto the beam. Their top side doesn't have texture, so you will need to be careful and look for places where beams cross for clue.


Bring another cube on top of that beam. Place it in this spot:


Now you can crouchjump from this cube onto the pipe on your right. It is a bit tricky, so save before the jump (it is generally good to save often; interacting with stacked cubes can be very janky).


Bring another cube. Place it in this spot, that way you will be able to acces it from the pipe:


Get on the pipe. Take your cube and stow it somwhere on the pipe, then bring another the same way. Place one of your cubes in this spot:
It is not level, so you need to place cube as close to the protrusion on the pipe as possible. Place another cube on top of the first one, again with a small ledge, then climb on the blue beam above:


Bring there two cubes and place them in this spot in a familiar fashion, then jump onto the pipe:


Congratulations! You now reached the highest point in that room that one can reach without cheating (and wasted an hour and a half of your life doing so). Well, kinda. There is a vertical beam behind that pipe in the corner, that ends abruptly about 5 cubes higher than the pipe you are standing on. Its top has collision, so in theory one can stack a ladder 5 cubes high and reach this point legitemately. That ladder would be very unstable, though. I'm not doing that. Nope.

There is another out of bounds spot on the map you can reach with the help of Cubes.
You can safely walk on the lower part of sloped surface next to shredder, and this vent doesn't have collision:


Place 5 of them here like so:

Then spam crouchjump and hope it will not take too long. From here you can jump into a small pit, where one of the walls lack textures. Here's what you can see through it:

Remember when I told you that you need to shutdown fans in the room with conveyor? Screw that. Your mighty Cubes can give you the power to completely skip interaction with both fans in this map.

First thing you have to do for achieving this is to smuggle two cubes behind Anti-Expropriation Field between two parts of the map. You can do that by placing them onto this vent:

It is done by running up the lower part of the slope leading to the shredder and crouchjumping right before touching the upper part of that slope. Those two cubes will be in your disposal after you cross the windswept part of the map.

Then, build a 4 cubes high staircase in this spot, which is unaffected by wind:


From it you can get onto invisible wall above catwalk fencing. Bring 3 cubes on top of the control room and use them to climb onto the first pipe. Jump down from it in this spot while continiously moving forward, it will be enough to get to the other side:


Walk this vent and get your two cubes. Haul them through portals onto catwalk leading to the second control room, then build 2 cubes high ladder in this spot:


Climb that ladder. From it, you will be able to get on the invisible wall over this catwalk fencing, because the invisible wall has slope when over staircases.


Jump down from invisible wall to this spot:


Fencing here does not have collision, and there is a very conveniently placed box in the corner, which you can use to get back to intended route.

Congratulations again! You have bypassed two easiest puzzles in the game by spending an hour or so of your life. And I have wasted 4 7 hours of my life jumping around that map and writing this. Hope you enjoyed it for I sure didn't.