About the book: 2021 / In many textbooks and articles, when explaining the essence of the curvature of space-time, leading to the emergence of gravitational force, the force of attraction, the metaphor of a rubber sheet is used. A massive body is placed on the sheet and other small bodies are shown rolling towards it along the curved surface of the membrane. However, this metaphor is misleading, creating a sense of three-dimensionality of the structure. In this case, small bodies can only roll under the influence of gravity. Explaining gravity using gravity is an incorrect way. The deflection of a rubber sheet is not really related to the third dimension. In fact, the bending of the membrane should be considered as a function of the attractive force. We call this deflection of the membrane a gravitational funnel, literally a three-dimensional force graph. All bodies in this design can only move along a plane of two coordinates; there can be no rolling into a funnel.