A pdf version of the paper to appear in PRL, "Imaging electron interferometer" can be found here.   There are two movies associated with Figure 3.  These show how the fringes move as function of reflector voltage.  The left one is taken at the same distance as the reflector and the fringes move at the same rate as the gate.  Figure 3 (a)-(e) is a subset of the data from this movie.  Each frame in the movies is a change of gate voltage of 20 mV.  The right movie is from twice the distance of the reflector and the fringes move twice as fast as the reflector gate.  Figure 3 (f)-(j) is a subset of this movie.  The fringes moving twice the speed of the reflector gate is because they are due to interference between trajectories hitting the tip and ones that have a double bounce off the reflector gate.

Single-bounce movie: The spacing of the fringes is about 20 nm.  Fringes move a total of about 55 nm. Colored dots are guides to the eye to watch the fringe movement.	Double-bounce movie: Same spacing of fringes, 20 nm.  Now, the fringes move twice as fast, a total of about 110 nm.  Colored dots are guides to the eye to watch the fringe movement.