Have you ever noticed patterns in nature? Such as the different time the sun rises each

day, or the schedule of the ocean tides?

How about patterns in your school work? Poems, such as limericks have a pattern that sets

them apart as a type of poem. Shakespeare’s plays contain patterns--they are written in

unrhymed iambic pentameter which is a pattern of ten stressed and unstressed syllables.

Patterns can be identified in art, as well, such as Van Gogh’s distinctive brush strokes.

In the process of observing and breaking down a problem into easier to solve smaller pieces,

you will likely have noticed similarities and patterns. You may have identified patterns

within the subproblems or among them.

For example, returning to the necklace problem, you may have noticed similarities between

each of the smaller subproblems identified:

What is the cost of the red beads? What is the cost of the blue beads?

What is the cost of the thread?

The operation to find each answer is the same:

Cost of red beads x number of red beads Cost of blue beads x number of blue beads

Cost of thread x length of thread

Each subproblem calculates the cost of the material by determining how much of each material

was used. This pattern of similar subproblems aids us in determining how to find the answer

to the larger problem. Stay tuned as we will continue with this problem in the next video.

Patterns are opportunities for efficiency when solving problems.

Being able to recognize patterns is a fundamental step in the process of problem solving with

computational thinking because the patterns help you determine what operations can and

need to be done. This is critical in moving forward in computational thinking, especially

if the goal is utilizing computers to automate and streamline a process. If the same operation

occurs again and again, it may be able to be entered once and repeated.

Let’s explore some classic examples of patterns in problem solving.

Codes are systems of symbols used to represent other symbols to disguise messages. To be

able to decode this type of message, the user must identify the pattern used for symbol

substitution.

For example, a very simple code might be based on a pattern of numbers representing letters,

such as 1=A, 2=B, 3=C, etc.

To make a code like this more difficult to break, the letter number patterns may be shifted—1=M,

2=N, 3=0, etc.

When trying to decipher a code, the decoder has to recognize the pattern being used for

the code in order to break it…unless they are lucky enough to have a decoder ring. Decoder

rings are mechanisms that efficiently use the code pattern to unlock a code based on

symbol substitution.

The most famous “decoder ring” in history is the Rosetta Stone. The Rosetta Stone is

an actual stone that was discovered in “Rosetta” (el-Rashid) Egypt in 1799. Prior to its discovery,

the hieroglyphs of ancient Egypt remained a mystery, as knowledge about what they meant

had been lost over time. The importance of the Rosetta Stone is that the same passage

was carved into the stone in three different languages. Codebreakers were eventually able

to use a language they knew to learn what the symbols they didn’t understand meant,

thus unlocking the secret to reading hieroglyphs and learning about ancient Egypt.

Cholera in London Another example where pattern recognition

played a role in problem solving occurred in London in the late 1800’s. Many of London’s

residents were ill with cholera (an infection of the small intestine that can lead to vomiting,

diarrhea, dehydration and eventually death), but disease spread was poorly understood at

the time, so it was unclear what the source of the outbreak could be. Through investigation

and deduction, a London doctor named John Snow hypothesized that Cholera was spread

through contaminated water and identified patterns as to when and where illness was

occurring in relation to water sources to locate the cause of the outbreak, one certain

contaminated city water pump.

In John Snow’s own words: “On proceeding to the spot, I found that

nearly all the deaths had taken place within a short distance of the [Broad Street] pump.

There were only ten deaths in houses situated decidedly nearer to another street-pump. In

five of these cases the families of the deceased persons informed me that they always sent

to the pump in Broad Street, as they preferred the water to that of the pumps which were

nearer. In three other cases, the deceased were children who went to school near the

pump in Broad Street...”

Due to John Snow’s pattern recognition and problem solving skills, the pump was disengaged,

the cholera epidemic was stopped, lives were saved and our understanding of waterborne

diseases grew.

A third example of pattern recognition used for problem solving is more recent. Around

2007, an art collector purchased this chalk on vellum (animal skin) drawing of a young

girl. He boldly suspected that the artwork could be attributed to Leonardo Da Vinci,

painter of the Mona Lisa and The Last Supper. Experts from the art world got involved and

started looking for patterns--features of the piece that were consistent with known

Da Vinci style, as well as other scientific and historic clues that might mean it was

a Da Vinci work. Through their investigation they found a long list of evidence (enough

to publish a book on the topic) that the drawing was in fact created by Da Vinci. The patterns

identified include: • exquisite details, such as the way the

girls headband curves her hair and her fine eyelashes

• the age of the vellum, determined through carbon 14 dating, on which the girl is painted

is consistent with when Da Vinci lived • pen and ink lines discovered under the

chalk layer using super high resolution photography that indicated a left handed artist (which

Da Vinci was) as well as similar drawing habits to Da Vinci’s other works

• A fingerprint preserved in the chalk--which unfortunately turned out to be inconclusive

• attempting to recreate a copy of the artwork in the same style determined that the materials

and style were very unique, used experimental binders to make the chalk stick, and would

have been challenging to work with--Da Vinci similarly experimented with binders when working

on The Last Supper • The girl in the drawing’s hairstyle

was identified to be from Da Vinci’s time and more specifically attributed to a specific

royal family for whom Da Vinci served as an artist. The girl was identified to be the

daughter of Da Vinci’s employer. • Finally, the jagged left edge of the vellum

and three small holes led to experts to believe the drawing came from a page in a book. The

book was traced to the National Library in Poland where it was found to match exactly.

Since Computational Thinking can be used in any subject area, the type of patterns to

be recognized vary widely. Let’s look at how pattern recognition can be used to address

some different types of problems.

The Computational Thinking activity provided by studio.code.org is an excellent offline

activity that demonstrates the Computational Thinking process visually as students “make

a monster”. The decomposition and pattern recognition steps are closely related in this

case, so both are introduced here. This activity will be used again in the last two videos.

The goal of the activity is for students to design an efficient method (program) for others

to be able to recreate drawings of monsters with unique sets of features. These are the

monsters.

The first step is decomposition and pattern finding. What features do these monsters have

in common? How can we group features? Ask students to list/group features.

What do all the monsters have in common? • They all have a head

• They all have eyes • They all have a nose

• They all have a mouth • Two have ears, one does not

Next, have students use tracing paper to physically group features. They can name the features

based on the monster’s name. We will continue with this activity in the next video.

There are many, many great online resources for practicing recognizing patterns. Visit

the suggested activities for this section to find links to a variety from different

subject areas. Several are described here.

The Pattern Generator at shodor.org generates an ongoing variety of different types of patterns.

If you want to focus on numbers and math related-patterns, try The Empty Triangle and Number Cracker.

For English/Language arts-related patterns try Syntax Store, which focuses on sentence

structure and Limerick Factory which plays with poetry.

People Patterns combines visual pattern recognition with math in levels of increasing difficulty.

Guess my Button is another visual pattern recognition game.

Another great way to practice recognizing patterns is through drawing. Students can

search for instructions and methods for drawing just about anything they would like. For example,

a quick search resulted in a method for sketching a horse that begins with abstract shapes and

steps through a process toward a detailed and recognizable horse. A similar method is

used when drawing a portrait.

When you have finished watching this video, don’t forget to complete the quick self-evaluation

to check your understanding.