|Yes, it's one continuous line.|
So last night I was drawing (as I am wont to do) and I ended up with, well... this.
And I thought, hey, cool.
And then I thought, you know what this illustrates really well? The difference between distance traveled and displacement.
Total distance is exactly what it says on the tin. It's the distance that you have traveled, regardless of direction (toward or away from the origin).
Displacement does take into account direction of travel, and is the shortest distance between your starting point and end point. (I've circled both points in red on the off chance that you can't figure out where each one is.)
As long as I'm applying physics to doodles, I might as well add that my marker speed was pretty much constant, but my velocity was not. Speed is distance traveled over time; velocity measures speed and direction. I made a lot of crazy little turns there. (I mostly tried to avoid looks and crossing over previously established lines, though. It would have made it look confusing.) In fact there were velocity changes out, as I believe the scientific term is, the wazoo.
If you wanted to calculate my average velocity, you'd take the distance between the handily-circled points and divide it by the time it took me to draw this (a long time). If you wanted to find my average speed, you'd have to find my total distance and then divide it by time.