Many textbooks and articles use the metaphor of a rubber sheet to explain the essence of space-time curvature, which leads to the emergence of gravitational force, the force of attraction. A massive body is placed on a 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 move only along a plane of two coordinates; there can be no rolling into a funnel.