import espressomd
import espressomd.constraints
import espressomd.visualization

system = espressomd.System(box_l=[40, 40, 40])
system.time_step = 1e-2
system.cell_system.skin = 1.2
system.constraints.add(espressomd.constraints.HomogeneousMagneticField(H=[0, 0, 10]))
visualizer = espressomd.visualization.openGLLive(
    system, background_color=[1, 1, 1], LB_draw_velocity_plane=True)
visualizer.lb_is_cpu = True
visualizer.run(0)