A hyperboloid of two sheets is a disconnected surface consisting of two symmetrical parts (sheets), opening in opposite directions along an axis.
\[ \frac{x^2}{a^2} + \frac{y^2}{b^2} - \frac{z^2}{c^2} = -1 \] where \( a, b, c \) are constants and the surface opens along the z-axis.
