Matrix3dIsXYRotation

Heads up/Tip this guy returns True if the there is a rotation, as in

If Matrix3dXYRotation(view.Rotation, angle) Then
. . . do something . . .

But what's not obvious is that angle is a holder for the rotation angle. So angle can be initialized to 0. And if the view is rotated pi/4 radians, say, then angle is returned with that value. Like I said, not obvious. There are probably other Is type methods that do this.