A change could be made from one choice to another to change idioms, and any of the parameters for a particular idiom can be changed. Any aspect of visual encoding can be changed, including the ordering, any other choice pertaining to the spatial arrangement, and the use of other visual channels such as color. A change often requires a set of items or attributes within the vis as input. There are several choices about how a user can select elements: what kind of elements can be targets, how many selection types are supported, how many elements can be in the selected set, and how to highlight the elements. The possibilities for how the view changes can be based on any of the other design choices of how to construct an idiom: change the encoding, change the arrangement, change the order, change the viewpoint, change which attributes are filtered, change the aggregation level, and so on.