How to make FDTD 1D transmission line and Creating a reflected voltage waveform movie by connecting 50-100-200 ohms using FDTD.

I want to make 1D transmission line FDTD and Creating a reflected voltage waveform movie by connecting 50ohm-100ohm-200 ohms using FDTD.

I attached a picture that is an example.

i want to know the code showing the graph and how to make a movie using that plot like the picture what i attached.

if you know only plot the graph and you don't know how to make the movie, it;s okay.