An automated storage and retrieval system , comprising: a storage and retrieval machine including a retrieval tool adapted to engage a container , wherein the retrieval tool is a gripper including spaced apart first and second gripper fingers , and wherein the gripper comprises actuators to enable the first and second gripper fingers to move apart or together with respect to each other; a storage unit including a shelf ; a plurality of containers configured as three-dimensional polyhedra disposed on the shelf , wherein adjacent containers are in contact, wherein a clearance is provided between adjacent containers to facilitate access by the first and second gripper fingers of the retrieval tool , and wherein the clearance is a partial separation which is created by one or more chamfers, fillets or bevels (236; 256) so that adjacent containers are in substantial contact; wherein at least one of the retrieval tool , the containers , and the shelf is configured to facilitate access by the retrieval tool to an individual container of the plurality of containers ; and wherein the gripper is adapted to be positioned so that the container to be grasped is between the spaced apart first and second gripper fingers , to activate the actuators to close and clamp the container between the gripper fingers , such that the gripper is moved to lift the container with the container held by the clamping force between the first and second gripper fingers and the frictional forces between the surface of the container and the gripper fingers prevent the container from sliding, wherein the partial separation is formed into a corner or vertical edge of said individual aligned containers and the partial separation is formed at the intersection between the front panels and the first and/or second side panels of the individual aligned containers . a storage and retrieval machine including a retrieval tool adapted to engage a container , wherein the retrieval tool is a gripper including spaced apart first and second gripper fingers , and wherein the gripper comprises actuators to enable the first and second gripper fingers to move apart or together with respect to each other; a storage unit including a shelf ; a plurality of containers configured as three-dimensional polyhedra disposed on the shelf , wherein adjacent containers are in contact, wherein a clearance is provided between adjacent containers to facilitate access by the first and second gripper fingers of the retrieval tool , and wherein the clearance is a partial separation which is created by one or more chamfers, fillets or bevels (236; 256) so that adjacent containers are in substantial contact; wherein at least one of the retrieval tool , the containers , and the shelf is configured to facilitate access by the retrieval tool to an individual container of the plurality of containers ; and wherein the gripper is adapted to be positioned so that the container to be grasped is between the spaced apart first and second gripper fingers , to activate the actuators to close and clamp the container between the gripper fingers , such that the gripper is moved to lift the container with the container held by the clamping force between the first and second gripper fingers and the frictional forces between the surface of the container and the gripper fingers prevent the container from sliding, wherein the partial separation is formed into a corner or vertical edge of said individual aligned containers and the partial separation is formed at the intersection between the front panels and the first and/or second side panels of the individual aligned containers . <EOS>