A recoiling energy absorbing system configured to be interposed between an outer layer that is exposed to impact and a foundation, the recoiling energy absorbing system having: energy absorbing modules, at least some of the modules being provided with:. a base configured to be juxtaposed with the outer layer;. edges (A-B, B-C, C-D, D-A) between which the base extends,. energy absorbing units extending from the base as frustroconical projections, the energy absorbing units having each: a flexible wall that extends from the base in a direction which is intended to be away from the outer layer; and a floor extending across the flexible wall and configured to be positioned adjacent the foundation; wherein the energy absorbing units are configured to at least partially absorb energy generated by an impacting object by the flexible wall bending inwardly or outwardly and recoiling after impact to or towards an undeflected configuration; characterized in that:. the energy absorbing units are oriented in a packed hexagonal arrangement. the modules are furthermore provided with friction means for impeding slippage, the friction means being configured to extend from the floor of at least some of the energy absorbing units and toward the foundation or from the base towards the outer layer;. the modules being furthermore provided along at least some of said edges with means for interlocking including energy absorbing units along an edge (A-B, B-C, C-D, D-A) of an energy absorbing module to be received by energy absorbing units disposed along an edge of an adjacent energy absorbing module for interlocking. energy absorbing modules, at least some of the modules being provided with:. a base configured to be juxtaposed with the outer layer;. edges (A-B, B-C, C-D, D-A) between which the base extends,. energy absorbing units extending from the base as frustroconical projections, the energy absorbing units having each: a flexible wall that extends from the base in a direction which is intended to be away from the outer layer; and a floor extending across the flexible wall and configured to be positioned adjacent the foundation;. a base configured to be juxtaposed with the outer layer;. edges (A-B, B-C, C-D, D-A) between which the base extends,. energy absorbing units extending from the base as frustroconical projections, the energy absorbing units having each: a flexible wall that extends from the base in a direction which is intended to be away from the outer layer; and a floor extending across the flexible wall and configured to be positioned adjacent the foundation; a flexible wall that extends from the base in a direction which is intended to be away from the outer layer; and a floor extending across the flexible wall and configured to be positioned adjacent the foundation; wherein the energy absorbing units are configured to at least partially absorb energy generated by an impacting object by the flexible wall bending inwardly or outwardly and recoiling after impact to or towards an undeflected configuration; characterized in that:. the energy absorbing units are oriented in a packed hexagonal arrangement. the modules are furthermore provided with friction means for impeding slippage, the friction means being configured to extend from the floor of at least some of the energy absorbing units and toward the foundation or from the base towards the outer layer;. the modules being furthermore provided along at least some of said edges with means for interlocking including energy absorbing units along an edge (A-B, B-C, C-D, D-A) of an energy absorbing module to be received by energy absorbing units disposed along an edge of an adjacent energy absorbing module for interlocking.. the energy absorbing units are oriented in a packed hexagonal arrangement. the modules are furthermore provided with friction means for impeding slippage, the friction means being configured to extend from the floor of at least some of the energy absorbing units and toward the foundation or from the base towards the outer layer;. the modules being furthermore provided along at least some of said edges with means for interlocking including energy absorbing units along an edge (A-B, B-C, C-D, D-A) of an energy absorbing module to be received by energy absorbing units disposed along an edge of an adjacent energy absorbing module for interlocking.