**Introduction**-
- Problem avoidance
- Just do it!
- Outlook determines outcome
- The weakest link
- The moving target

**Strategies**-
- Divide and conquer
- Find a better tool
- Identify a more general problem
- Compute or simplify
- Find a better perspective
- Find a better perspective II
- Find a pattern
- Think in a new dimension
- The greedy method
- Question everything
- Make a model
- Exercise both halves of your brain
- Practice "free association"

**Pending**-
- Bring me a rock
- Start stupid and evolve
- Stepwise decomposition
- "Exploratory programming"
- Keep it simple
- The 2 rules of reuse

## The comprehensive entrance test for Navy flight school:

1. What is the first thing you do when you step into the stall?

to get the soda machine to accept her dollar bill.

She asked for assistance.

I helpfully pushed the Coke button,

one popped out, I grabbed it, and started walking away.

Now cleared of the "problem", the machine accepted her dollar.

Her reply: 'Thank you.' "

Occam's razor -- start with the simplest/obvious solution Don't untie the Gordian knot -- cut it! "Use a bigger hammer"

A poet walks through a field and picks up burrs on his wool trousers. He describes the experience esthetically, "How nature attaches itself to man."The same thing happens to a comedian. That night, he gets onstage and complains, "What is it with these burrs? God's way of getting even with me for walking on the grass?"

An engineer walks through the field, and then spends 5 years in the lab to invent Velcro.

All three experienced the same reality; yet only one saw an opportunity, and solved a problem.An engineer takes a problem and fixes it. A humanist takes a problem and celebrates its complexity.

[Robert Weisbuch]

How would you solve this problem? What does X represent? (Click on the diagram.)

So this problem can be divided into 2 sub-problems: compute R1, and compute R2.

We know the formula for the circumference of a circle. We know the value of C. We know how to convert 25,000 miles into a comparable number of feet. How would you compute the value of R1? (Click on the diagram.) Do the math. (Click) How would you compute the value of R2? (Click) Do the math. (Click)

Now, X can be computed from the 2 sub-problems. (Click)

Plug equations 2 and 3 into equation 1. (Click) Expand the expression on the right side. (Click) Eliminate the factor common to both sides. (Click) Divide both sides by 2. (Click) Solve for X. (Click)

What happened to R1 and R2? They are gone!!! Using this more elegant approach (and resisting the urge to simply "plug and chug") not only eliminated most of the tedious (and error-prone) arithmetic; but it also generated remarkable insight — this problem is totally independent of the size of the sphere!!!

"The more general problem is often easier to solve, and in programming, the more general design may be easier to implement, may operate faster on the machine, and can actually be better understood by the user. In addition, it will almost certainly be easier to maintain, for often we won't have to change anything at all to meet changing circumstances that fall within its range of generality."

The previous problem demonstrated 2 different approaches:

- Focus on the trees, keep your head down, and don't look up until the problem
is vanquished.
- Focus on the forest, and identify a more general problem.

Click on the diagram, for another representation of the problem. Do you know the radius of the cylinder? How about the radius of the sphere? Using the "more general problem" strategy, the volume of the sphere remaining can be expressed as:

volume remaining = (volume of sphere) - (volume of cylinder) - (volume of top and bottom end caps)Using geometry as a tool, the right side results in the following equation:

(4/3 * pi * R2^{3}) - (pi * R1^{2}* H) - 2 * (1/6 * pi * K * (3 * R1^{2}+ K^{2}))

After a page of algebra, we could derive an answer of –
1/6 * pi * H^{3}

BUT, is there any way to "massage" this problem in order to *simplify*
it? How many different sized spheres can "contain" a 6 inch tall hole?
How large is the radius of the cylinder? Do we know?
Do we care? Click on the diagram to see 4 possible configurations.

Is there an inference you can draw from this series of examples that makes the problem trivial? Click again for the answer.

What is the area of the smaller square?

Does it help to rotate your perspective?

To rotate, the inner square, click on the diagram.To add two diagonal lines, click on the diagram.

What if you rotated the pattern 90, 180, or 270 degrees?

Click on the diagram four times.

- "you just me" encodes the phrase "just between you and me"
- "COLOWME" encodes the phrase "low income"

For a series of hints, click on the wordle once, then again, then again, ...

For the answer, click on the statement.

A common problem solving method "takes life in big bites". If the choice is between a moderate/humble/steady step, and an aggresive/selfish/impulsive step; always choose the latter. It's like the jar, rocks, and sand demo. If you put sand in the jar first, then only a fraction of the rocks wih fit. But, if you put the rocks in first, then the sand will easily fit in the jar.

The game of Set started as a model for examining epilepsy in German Shepherds. The population geneticist studying the problem used several shapes, colors, and other graphical attributes to model blocks of common and distinct genetic traits. This coded information was recorded on dozens of index cards and spread out on a table. The cards were moved, swapped, and grouped until useful patterns could in discerned.

Each card captures 4 dimensions of information: **shape** (X, O, or rectangle),
**number** (one, two, or three), **color** (red,
green, or blue),
and **fill** (open, striped, or solid).

A set consists of 3 cards where each dimension across all 3 cards is the same or different. "Same" means all 3 cards use the same symbol, the same number of symbols, the same color, or the same fill. "Different" means one card is red, one is green, and one is blue; OR, one is open, one is striped, and one is solid; etc. It does not mean one is red, and two are green.

Click on the game seven times to see the sets highlighted one at a time.

A remarkable property of this game is: given any 2 cards, there is one (and only one) card that will form a set. Click on the game. Identify the one card that will complete the set. Do the same for the remaining five sets.

cottage blue mouse"associated" could mean a two-word phrase like "summer cottage" or "cottage cheese" or "blue moon". It could also mean a word that is routinely thought of as linked or descriptive of the other word, like "cottage has a roof", "blue is a color", or "mouse eats cheese". In this case, the answer is

This "Remote Association Test" is based on the inventor's theory of associative creativity. The creative thinking process is the forming of associative elements into new combinations which either meet specified requirements, or are useful in some way. The more mutually remote the elements of the new combination, the more creative the process or solution.

Solving these puzzles requires the individual to consider a number of meanings for each word, getting past typical uses of words, and searching for rare associations that might fit with all 3 words. The selection and recombination of remote ideas is thought to be an important process underlying creativity and innovation.

Creative people differ from others in the way their network of facts/memories/ideas are linked (i.e. the way their associative hierarchy is organized). Creative individuals have a flat hierarchy – each element is connected to many others. Less creative people have steep hierarchies in which each element evokes or cascades or links to very few other elements.

Try your hand at 68 of these puzzles above. Type an answer and press <Return>. If you would like help, type "hint" and <Return>. If you want the answer, type "i give up" and <Return>. Pressing <Return> by itself advances to the next puzzle without revealing the answer to the current puzzle.

Experience is the result of bad judgment.

We frequently observe that the more elaborate "develop for reuse" analysis process can be profitable even if we choose not to develop the component for reuse. For example, the search for a more general solution and the study of other potential reusers can uncover hidden requirements from the customer, lead to a more complete and adequate solution, and avoid costly changes when problems arise due to missing functionality.