[yashg]

As usual, I am too dumb to understand this.

[fragmede]

the balls go in and want to go out. top right there is a wrench icon. click that and gain access to some tools, with which you can guide the green and blue balls into their respective destinations. how fanciful the machine to guide the balls is up to you.

[meta-level]

You forgot to mention that each level is part of a colaboratively built machine