# When a relevant variable unnamed on either axis changes, can the curve NOT shift?

Source: pp 40-41, Principles of Microeconomics, 7 Ed, 2014, by N Gregory Mankiw

her demand curve would shift to the left (to curve D3). In economics, it is important to distinguish between movements along a curve and shifts of a curve. ...
♦ There is a simple way to tell when it is necessary to shift a curve: When a relevant variable that is not named on either axis changes, the curve shifts. ♦ ...

Is the last sentence of the excerpt (within $\mathbb{R^2}$) above really true ? (I surrounded it with lozenges ♦)

What if ceterus paribus, a fixed number $> 1$, of relevant variables changes? Can they counteract each other, or even equilibrize all the changes so that the curve stands unmoved?