Add rotate?

[Fil]

In multitouch, by following the angle between fingers it's possible to rotate objects, as demonstrated in "Attitude zooming" https://observablehq.com/d/7a912fba32fbe641?collection=@d3/d3-zoom

This part of the gesture could be included in d3-zoom to help to rotate objects on the plane (e.g. photos on a table).

However it's not clear to me how we would rotate without multitouch (grabbing by a corner, or using a modifier key?).