Duncan Jones' Production Doodle Explains 'Source Code'

Duncan Jones' Source Code hit Blu-ray and DVD a few short weeks back and while most film nerds have exhausted any talk of the film's ending, more and more people are now discovering the movie. Seems like the perfect time for the director to take to Twitter and post a drawing he did during production that attempts to visually explain the film's structure, ending and subtle changes. Obviously, there are major Source Code spoilers after the jump.

Thanks to Rope of Silicon for the heads up on this drawing, which originated at Duncan Jones' Twitter.

Basically this is the much more complicated version of Doc Brown's explanation of the alternative, Biff-Co 1985 in Back to the Future 2 where time veers off into alternate realities.

As far as I can tell, this actually changes my interpretation of the movie. I thought each trip Colter Stevens (Jake Gyllenhaal) takes through the source code, he bends the possibilities of reality but is always drawn back to the original reality of the train exploding, signified by the X-axis, until, finally, he succeeds and creates a new reality, the Y-axis.

That's sort of true but, if you follow Jones' drawing beginning on the bottom left towards the right then up and down the arrows, there are actually several realities created by the film whenever a significant change occurs. Stevens keeps getting closer and closer to the ultimate fix but never quite gets there and is always drawn back. Notice the direction of the colored arrows, those signify Stevens going back and forth to different places and in doing creating multiple realities. He keeps coming back to the X-axis because the train keeps crashing but, once it doesn't crash, he creates the Y-axis, the new reality he's staying in.

I haven't taken math in about a decade so maybe I'm wrong in my interpretation. What do you make of this?