# Supply and Demand plotted on a three dimensional Cartesian coordinate system

Is it possible ? if it's possible can someone give me a reference ? Thanks !

It is possible. Trivially if we have $$Q^s=f(p)$$ and $$Q^d=g(p)$$ and we plot this in a 3d-coordinate system with variables $$p$$, $$Q$$ and some other variable $$x$$ (which does not appear in our functions at all), then we can take a 'slice' for every $$x$$-value, and in fact every slice gives us the conventional 2d-depiction of this model.
$$Q^s(p,t)=\max(0, p-t), \quad Q^d(p,t)=\max(0, 1-p)$$
Where $$t$$ is a unit tax imposed on the suppliers of the good in question. We can plot this in a 3d coordinate system with variables $$Q,t,p$$ and a red line showing equilibria: