Just enjoy yourself! Different choices of the initial k give a rich variety of real space orbits. Note that the time averaged motion is always in the y-direction, though the electric field is in the x-direction--a remnant of free electron behavior. What is strange, of course, is that sometimes this average motion is in the positive y-direction and sometimes in the negative direction, depending upon the choice of initial k. For hints on interpretation of these orbits, see Ashcroft and Mermin p. 233.
Compare the real space trajectories using the preset parameters except with the E-field changed first to 0.10x(10^6 V/m) and then to 0.15x(10^6 V/m). that and sometimes