def wheelDown(event):
    """Map mouse wheel down displacements to rotations about Z axis."""

    global tet
    tet = matMul(ROT_Z(EPS(-1)),tet)
    drawTet(tet,tetColor)
Map mouse wheel down displacements to rotations about Z axis.
recipes/Python/578876_Rotatable_Tetrahedron/recipe-578876.py