NL-NWO 1998 Problem 2

Let $TABCD$ be a pyramid with top vertex $T$ , such that its base $ABCD$ is a square of side length 4. It is given that, among the triangles $TAB$ , $TBC$ , $TCD$ and $TDA$ , one can find an isosceles triangle and a right-angled triangle. Find all possible values for the volume of the pyramid.