How to use GNU Make to make movie from indexed data files?

Question

I'm trying to use the linux utility make in order to

1. Run a script to generate the data
2. Take all of the output files (data1.txt to data79.txt) and run a script to plot them each
3. Take all those images and make a movie from them

Yes, I realize that doing this in a shell/python script would be downright simple but I'm trying to learn how to use make in this context to do the work more intelligently.

My current make file looks something like this but is significantly flawed:

movie: data *.png 
    ffmpeg data_%d.png output.mp4

%.png: %.txt
    python plot.py $< $@

data:
    python make_data.py