then the program should look more or less like to be functional. I enclose a photo of the finished program.

we have a work area, a ruler, comment on the unit of measure, a long, fast, 1s = 100ns, slow, 1s = 30ns, or very fast, 1s = 500ns.

you can set the  work area  in millimeters, both x and y.

you can set the field B in tesla.

in the image there is a error!!! the velocity must be V=v*10'000 m/s and not V=v*1000 m/s because the v range between 0 and 1.