General Problem Solving

The Four Steps of Problem Solving * Orient Plan Execute Test These apply to any kind of problem, not just programming or process design * [Carlson and Bloom, “The Cyclic Nature of Problem Solving: An Emergent Multi-Dimensional Problem Solving Framework”, Educational Studies in Mathematics, Vol. 58 Number 1, 2005] 2

A Simple Example: Crossing the Street Orient: Gather information: amount of traffic, traffic lights, sirens? How does traffic work? Do cars stop for lights? Do bikes? Do pedestrians? Plan: Consider various approaches. What if I jaywalk? What if I walk to the corner and cross? Execute: Cross the street. Check: Did I make it safely? Were there any unexpected hazards? Should I keep using this approach or modify it next time? 3

Crossing a Portland Street 4

Portland Street Anyone who has spent time in the US can cross this street safely. But do note there is some construction going on, and there is a walk button (not visible in the photo) that you need to push to get a walk signal. If you hear a siren, you need to know to stay on the sidewalk. 5

Crossing a Street in HCM City 6

Hochiminh City, Vietnam Tourists have a very hard time crossing the street safely in HCM city. In fact there are special police to help you in the tourist areas! As far as I can tell, motorbikes can go through most red lights whereas cars and trucks have to stop. It is ok to cross a street full of motorbikes if you walk slowly and steadily, but never step in front of a car, bus, or truck! 7

The Arc de Triomphe 8

Getting to the Arc de Triomphe 9

Arc de Triomphe The Arc is in the middle of a huge busy traffic circle You could get killed crossing the street over to the island where the Arc is… unless you happen to notice the underground tunnels for pedestrians! 10

Oxford Street, London 11

Oxford Street At this intersection, there is a part of the traffic light cycle where all vehicle traffic stops so pedestrians can cross. The next photo shows a similar intersection in Japan. 12

Shibuya, Tokyo 13 Picture credit Ben Waller,

And the moral is… Follow the process! (Orient, Plan, Execute, Check) Don’t just jump in and start trying something! Your previous experience may not exactly apply; the best solution may not be the first thing you think of. Take the time to analyze the problem before you start constructing the solution. In the end you will have a better solution in less time. 14