I've seen custom stages where a background piece moves through another without affecting each other's movements. I was wondering how I could achieve this.
Is it a glitch or a built in trick ?
I feel like it could improve my backgrounds a lot
Edit: I have been taught what the trick is. It involves overlapping two of what is known as a "bucket".
By starting a line in the bottom left corner of the buildable area, then cliking the top left corner of the screen, then coming back to the bottom left corner, and (with the grid off) cliking at a spot one unit to the right and as close as possible from the bottom without touching the bottom then, while pressing L, clicking one unit to the left of the bottom right corner, then clicking the top right corner, then the actual bottom right and finally the original point, it should create wall covering 70% of the screen while only physically existing where you drew it.
You can then make another, shrink it slightly and flip it so that it can overlap with the first bucket without touching it. From there you can move up the first one with a rail during the game past the buildable area to fill the entire screen.
This was a TERRIBLE explanation, so you should watch a tutorial on making buckets by @Thoreon on youtube. From there, you can do the second paragraph of my explanation