Briefly

Upside down stairs

Upside down stairs

In this image, at a glance we see stairs that climb from left to right. This is because it is the most "natural" way to see them. However, the image does not have enough information about perspective and it is also possible to see the inverted staircase so that the “wall” that we initially saw closer may be the farthest and the stairs are turned upside down. The highest “step” would be located on this occasion in the right part of the image.

Solution

At first it costs a bit to visualize this second interpretation of the image. You could see it more easily if it were possible to turn your computer screen and turn it upside down. Then we would see the stairs in the same position, as if we had not rotated the image.

Also, if you look at the drawing for some time, you will usually find yourself involuntarily changing the view frequently from a ladder viewed from above to a ladder viewed from below and vice versa.