Undoubtedly the two theories for which Einstein is known are the special theory of relativity (STR) and the general theory of relativity (GTR). These two theories enjoy very wide scientific consensus in modern physics. Although the space that these theories occupy in university books, in scientific papers and conferences, is very large, their use in practice is quite poor. This fact makes these two theories more exotic than useful. In what follows, we will ask two simple questions – one for each theory, and it will be shown that there is no answer/solution in the framework of these theories. Perhaps this explains why the theories are not as useful.
Question for the STR
Let a body denoted by P move so that its position in relation to the two resting observers O and O’ always creates an isosceles triangle. The system with the observer at O’ moves in relation to the observer at O with constant velocity 
(Fig. 1). The question is: What would be the condition according to the STR in order for this motion to happen? In other words, what would be the ratio between the velocity of the body P and velocity , in order for this motion to be carried out in an isosceles triangle? The STR has no answer in this question! Why? Without going into more in-depth reasoning, the STR has no answer to this question because this theory by definition does not allow 
. Indeed, according to this theory, moving bodies undergo contraction in the direction of motion, so is not allowed in the frame of the STR; therefore, the STR has no answer to this simple question.
Fig. 1. The motion of the body in an isosceles triangle between two observers.
Question for the GTR
Let there be two bodies with shape and mass ideally the same; let them be alone in space and away from each other at a considerable distance. The question is: what happens to these bodies according to the GTR? Will they move toward each other? According to the fundamental properties of the relationship between mass and space-time in the GTR – masses of the bodies curve the space-time. Since we are dealing with two ideally identical bodies that are located alone, then the GTR has only one answer to this situation: they curve the space-time alike, so they stagnate on place. But, the GTR’s solution is counter-evolutionary; it is against the general idea that material bodies interact with each other, in one way or another.
Fig. 2. Two same bodies in the space of GTR.
