Electron wave-packet interference
The green plane is the x-y-plane, where two (non-interacting) electron wave-packets meet. The vertical direction shows the real part of . The semi-transparent white plane in the top shows the density of detection probability, i.e., , as blue spots. The blue in the middle is the same again.
Before interfering, both electrons have circular detection probabilities. During the interference, you can see lines, where there are strong wave movements and others, with no motion in between. The lines without wave motion are called knot-lines. As you see, the detection probability is zero on knots. After the interference, both electrons move as if they never had seen the other one.
The smearing out of electrons is their usual behavior due to dispersion. It is independent of interference.