Thank you all more for trying to help me.
I think the triangle example was inappropriate.
Imagine the face of a person who has two eyes, a nose and a mouth.
There is an image (let's call it number 1), which depicts a person's face, with open eyes and closed mouth.
Then, I create another image (number 2) with only the left eye drawn and closed, and everything else in the picture has a transparent background.
Create image (number 3) with the right eye closed, everything else has a transparent background.
I create an image (number 4) where only the mouth is drawn and it is open, everything else in this image has a transparent background.
All of these images are the same size.
I need all these layers, to superimpose one on top of another, thus, in the program, I can make a certain layer visible or invisible.
Аll images have a transparent background, this means that the nose in the first image should not overlap all other layers (they are transparent) and on the first post (in another development environment) this is exactly how it works...
But in MIT APP the upper layers of the images overlap the lower ones, although their background is transparent.
To be honest, I thought that the solution in MIT APP would be much easier)