Aspects of the disclosed technology present a workspace window responsive to a relationship data structure that represents a comprehension state including a presentation of a first instance-representation that represents a first separately-movable instance object and a second instance-representation that represents a second separately-movable instance object. This aspect enables the first instance-representation and detects when the first instance-representation is dropped within a threshold distance of the second instance-representation. When the first instance-representation is dropped, the technology identifies, responsive to the step of detecting, one of a plurality of spatial relationships between the first instance-representation and the second instance-representation. Responsive to the identified spatial relationship, the technology selects an operation, and responsive to the operation modifies a composite object in the relationship data structure. The composite object incorporates an entity/relationship object that is represented by the first separately-movable instance object and an entity/relationship object represented by the second separately-movable instance object. After the composite object as modified, an instance-representation that represents the composite object is presented in the workspace window.