As a basic rule of physics, it is possible to play a 2 track stereo tape on a 1/4 track stereo machine, but it is not optimal as the gaps are not aligned with the center of the track. It is not possible to play a 1/4 track stereo tape recorded both sides, on a 2 track machine as the left gap will read the left channel from side one forwards and the right channel from side two backwards simultaneously, and the right gap will read the right channel from side one forwards and the left channel from side two backwards simultaneously - a MESS !