Just thinking out loud... What if strings could interact in the same manner as quantum particles in that they can act both as particle and as wave depending on the observation apparatus. That is, there is a singular force in the universe which affects all things, by it can manifest in two forms. If you diffract the waves of this force by causing the strings to interact through moving electrons, then you get electromagnetic waves in a characteristic diffraction banding pattern. The electrons are like a a mesh screen or spaced slits. However, as you move to larger things and scale up, there are times when there is no more diffraction and the force acts as a particle would as there are no more "slits" to cause diffraction. This force could act as gravity does, uniformly in the 3D space except for diminishing with distance and increasing with mass.