1. A method for presenting a time sequence of editing steps in a two-dimensional document, the method comprising: accepting, at a first time on an electronic document editing device, a first editing command for a first two-dimensional object within a two-dimensional electronic document, the two-dimensional electronic document defining objects with a first dimension and a second dimension; accepting, at the electronic document editing device at a second time subsequent to the first time, a second editing command specifying a modification to a definition of the first two-dimensional object within at least one of the first dimension and the second dimension; and displaying, on a display device, a representation of a three-dimensional structure corresponding to the first two-dimensional object, the three-dimensional structure depicting at least one of the first dimension and the second dimension and representing time as a third dimension that is orthogonal to the first dimension and the second dimension, the three-dimensional structure representing a time interval between the first time and the second time as structural elements extending along the third dimension, the three-dimensional structure extending along the third dimension from a first time point corresponding to the first time to a second time point corresponding to the second time, the three-dimensional structure having components at the first time point in the first dimension and the second dimension that represent a view of the first two-dimensional object, the three-dimensional structure having components at the second time point in the first dimension and the second dimension that represent a view of the second two-dimensional object, the structural elements extending along the third dimension from the view of the first two-dimensional object to the view of the second two-dimensional object, the structural elements representing the modification to the definition of the first two-dimensional object as specified by the second editing command, the structural elements extending along the third dimension with first dimension components and second dimension components corresponding to the first editing command, and three-dimensional structure representing a time interval subsequent to the second time as a subsequent three-dimensional object representing the first two-dimensional object as modified by the second editing command, the subsequent three-dimensional object having subsequent first dimension components and subsequent second dimension components corresponding to the second editing command and extended along the third dimension, accepting, at a third time that is subsequent to the second time, a command specifying a modification to the first editing command; and updating, in response to accepting the command specifying the modification to the first editing command, the three-dimensional structure to reflect, at a point corresponding to the first time within the three-dimensional structure, the modification of the first editing command, the updating further modifying the three dimensional structure along the third dimension to reflect the modification of the first editing command.
2. The method of claim 1 , further comprising: accepting, at a third time that is subsequent to the second time, an input to undo the first editing command; undoing, in response to accepting the input to undo the first editing command, the first editing command, the undoing operating to return the first two-dimensional object to its condition prior to the execution of the first editing command; modifying, in response to accepting the input to undo the first editing command, the structural elements of the three-dimensional structure to remove effects of the first editing command between the first time point and the second time point; and modifying the subsequent three-dimensional object to remove effects of the first editing command.