There are at least two ways to make this impossible object. For one of
them we will need to improve one rod, for another - a frame.
In either cases to see reached impossible object correctly you will need
to look at it from the certain perspective.
Take four identical rods, the square frame with the four round holes in it
and make the composition shown in Figure 1.
Of course, we didn't get the needed object yet. For this cut the rod
nearest to you as shown in Figure 2, and make the final composition.
Take three rods (two - 1 unit each and one - 1,5 unit) and place the
square frame with four holes on them as shown in Figure 3.
To get the intended object we slightly improve the square frame as shown
in Figure 4. How to compose the final object is shown in the same figure.
(Note that the reached object can't balance oneself when placed on the