Thomas' Calculus 13th Edition

The form of the equation is $\displaystyle \frac{y^{2}}{1^{2}}-\frac{x^{2}}{1^{2}}=\frac{z}{1},\quad$ which is a Hyperbollic paraboloid (when comparing to Table 12.1). The cross sections with planes $x=k , y=k$ are parabolas, and the cross section with planes $z=k$ are hyperbolas.