The method according to the invention deals with controlling of graphical elements of a display having a plurality of pixels with one or more processors, the method including defining by said one or more processors a graphical main shape on the display representing a total volume of a root node, defining by said one or more processors within the graphical main shape a number of graphical node shapes on the display, the number of node shapes being at least one and each node shape representing a volume of a parent node, wherein the volumes of all parent nodes sum up to the total volume, controlling by said one or more processors the pixels of the graphical main shape to visually present the graphical main shape on the display, redefining the graphical node shapes in response to receiving an input signal from an input device indicating a selection of a parent node, indicating a manipulating of a volume of a selected node shape or indicating an opening of a particular parent node.