  The large-scale structure in the Universe is believed to arise out of small
random density perturbations generated in the very early Universe, that are
amplified by gravity. Large and usually intricate N-body simulations are
typically employed to model the complex nonlinear dynamics in a self
gravitating medium. We suggest a very simple model which predicts, on large
scales, the correct density and velocity distributions. The model does not
involve an explicit computation of the gravitational force. It is based on a
simple transformation of the variables and local conservation laws of mass and
{\it generalized} linear momentum. The model demonstrates that the overall
appearance of large-scale structure in the Universe is explicitly determined by
the initial velocity field and it reveals the most significant large-scale
effects of gravity on the formation of structure.
