Calculate Your Most Efficient Trajectory, and other walking games

Could not believe my eyes when I saw this madness on (er...) 9GAG the other day. 

OMG IT'S NOT JUST ME THAT DOES THIS.

Kids play walking games: 

Step on a crack, break your mother's back;  

Step on a line, break your father's spine

So do adults.

Here are the walking games I still play - cannot help playing - every time I walk:

1. Even Stevens
2. The Point of No Trace of Origin
3. Most Efficient Trajectory

Even Stevens

I no longer try to avoid stepping on lines. Please! I managed to stop that madness in my twenties! But I do have a thing quite often where I have to keep track of how I step on lines and keep things "even" with both feet.

Example: 

I've just stepped on a line with the ball of my left foot - therefore I have to do the same with my right foot. But so I don't stop short and shuffle my feet around and look like a weirdo I keep walking "naturally" but keep count of what I step on with both feet, until I can even the score of each item with the other foot. So the count I keep in my head might go something like: left one ball of foot, left one heel, right one middle of foot, left two ball of foot...

Of course at some point it starts to get too hard to keep track, in which case I DO quickly do a weird foot shuffle or stop and swap feet, so I can keep my feet even.

The Point of No Trace of Origin

I do this while city walking, when I've just passed through an intersection or turned a corner. Imagine someone got a snapshot image of you walking at a given point in or after the intersection. Based on your position on the footpath, distance from the curb or corner, length of your stride and angle of your body, at many points it must be possible to look at the snapshot and figure out whether you got there by crossing the street or turning the corner. At some point, as you go a little further, there is a point at which it would no longer be possible to tell which way you had come.  

As I walk I try to pinpoint where that point is. Sometimes I try to pass through an intersection in a way that would give away as few clues as possible as to whether I had come from straight behind or from around the corner. 

Most Efficient Trajectory

Like the 9GAG cartoon at the top - but in my case with frustratingly little math skill. Try and estimate or calculate the most efficient route between two points. That might not be the shortest one; it could be the one with fewest angles, the least foot traffic, more downhill slopes, etc. I spend a bit of time trying to figure out at what distance/number of obstacles a zigzag or series of corners is more or less efficient than a straight line, etc.  This is not to avoid walking, which I love - just another attempt to be more efficient through silly shortcuts.

Here's how I know I'm not the only one doing this:

Adult walking games in popular culture

I remember two references:

The first was an episode of Seinfeld where Jerry walks his date to his apartment door and tells her about a game he plays where he pretends he's being chased by murderers and when he gets to his door he has to unlock and open it as fast as possible to elude them.

Who hasn't played that game?

The second was a short film I saw years and years ago as a kid. When I was a kid, when you went to see a movie it went like this: ads; short film; interval; movie.  Shorts were a mixed bag. Most were boring, some were genius. This particular short one of the best I ever saw. It followed a Londoner on his morning commute into the city. All the dialogue took place in his head.  He is standing on a bus and looks around and picks three or four other passengers to "race" with. He assigns each a name like "Green Cardigan", "Umbrella" and "Bowler Hat". When they all get off the bus he starts narrating (in his head) in the style of a horse race: And they're off! Green Cardigan gets off to a fine start but Bowler Hat is way back... The narration continues as it shows him hurrying through the busy streets, taking little shortcuts, veering through foot traffic, all the while keeping an eye on the others as he tries to reach the finish first.  It's obvious these are all regular commuters going to the same street for work and he plays this game with different people every day. There are a couple of tense moments where he thinks he won't “win”, then he's on the home stretch and in front of everyone. Just as he's grinning smugly and striding to the "finish" he realises Bowler Hat is not behind him as he thought but in front. He gets such a shock at being about to lose the "race", that he loses his sanity – the film ends on a freeze frame as he cries out and grabs  "Bowler Hat" by the shoulder.

Do you play walking games? Tell me one!