What do you see in the image?The image can be challenging to interpret,and most people need a clue to see the pattern.It shows a Dalmatian dog.An interesting aspect of this experience is that once you've perceived the pattern,you can't unset the dog.

Whether we like it or not,our brains look for patterns in various contexts.Much of our everyday understanding is linked to the concepts we lean in school and through interaction with others.On top of this,there are learned cultural patterns to interpret works of art,music,poems,etc.Once we know the patterns,they profoundly influence how we perceive cultural products.So we see the world through patterns we have acquired.

These patterns can be applied in all forms of teaching.The great benefit of seeing a pattern in an area of knowledge is that it can be applied to new problems.A student who has understood a pattern can not only answer questions taken directly from the learning material but can use it in other types of tasks.The key question,therefore,is how a student can discover the relevant patterns and create real understanding.

There are different ways to highlight patterns.Analogies(类比)are powerful tools for creating understanding.An example is the number line(数轴)in elementary mathematics. When children learn addition,it is easy for concrete combinations of objects:three apples plus two apples make five apples.The same is true for subtraction(减法):If you have six apples and remove four,you are left with two.

But this doesn't work when it comes to negative numbers.How do you explain that if you have three apples and remove five,two are missing?Then,an effective analogy is to see the number line as something you walk along—the line becomes a path.Addition with three is like walking three steps forward,and subtraction with five is like walking five steps backward. No wonder that if you walk three steps forward and then five steps back,you are two steps behind where you started.

In this way,the negative numbers acquire a meaning rooted in experience.More patterns of numbers can now be understood.

Nowadays, the world is slowly becoming a high-tech society and we are now surrounded by technology. Facebook and Twitter are innovative tools; text messaging is still a somewhat existing phenomenon and even e-mail is only a flashing spot on the screen when compared with our long history of snail mail. Now we adopt these tools to the point of essentialness, and only rarely consider how we are more fundamentally affected by them. 

Social media, texting and e-mail all make it much easier to communicate, gather and pass information, but they also present some dangers. By removing any real human engagement, they enable us to develop our abnormal self-love without the risk of disapproval or criticism. To use a theatrical metaphor（隐喻）, these new forms of communication provide a stage on which we can each create our own characters, hidden behind a fourth wall of tweets, status updates and texts. This unreal state of unconcern can become addictive as we separate ourselves a safe distance from the cruelty of our fleshly lives, where we are imperfect, powerless and insignificant. In essence, we have been provided not only the means to be more free, but also to become new, to create and project a more perfect self to the world. As we become more reliant on these tools, they become more a part of our daily routine, and so we become more restricted in this fantasy.

So it is that we live in a cold era, where names and faces represent two different levels of closeness, where working relationships occur only through the magic of email and where love can start or end by text message. An environment such as this reduces interpersonal relationships to mere digital exchanges.

Would a celebrity have been so daring to do something dishonorable if he had had to do it in person? Doubtful. It seems he might have been lost in a fantasy world that ultimately convinced himself into believing the digital self could obey different rules and regulations, as if he could continually push the limits of what's acceptable without facing the consequences of "real life."

Holding the large and heavy "brick" cellphone he's credited with inventing 50 years ago, Martin Cooper talks about the future.

Little did he know when he made the first call on a New York City street from a heavy Motorola prototype(原型) that our world would come to be encapsulated on a sleek glass sheath where we search, connect, like and buy.

Cooper says he is an optimist. He believes that advances in mobile technology will continue to transform lives but he is worried about risks smartphones pose to privacy and young people.

"My most negative opinion is we don't have any privacy anymore because everything about us is now recorded someplace and accessible to somebody who has enough intense desire to get it," the 94-year-old said in an interview in Barcelona at MWC, the Mobile World Congress, the world's biggest wireless trade show, where he was getting a lifetime award.

Cooper sees a dark side to the advances, including the risk to children. One idea, he said, is to have "various Internets intended for different audiences."

Cooper made the first public call from a handheld portable telephone on a Manhattan street on April 3,1973, using a prototype device his team at Motorola had started designing just five months earlier.

Cooper used the Dyna-TAC phone to famously call his opponent at Bell Labs, owned by AT&T. It was literally the world's first brick phone, weighing 2.5 pounds and measuring 11 inches.

Cooper spent the best part of the next decade working to bring a commercial version of the device to market.

The call helped kick-start the cellphone revolution (革命).

Cooper said he's "not crazy" about the shape of modern smartphones. He thinks they will develop so that they'll be "distributed on your body," possibly as sensors "measuring your health at all times."

Batteries, he said, might be replaced by human energy. The body makes energy from food, he argues, so it could possibly also power a phone. Instead of holding the phone in the hand, for example, the device could be placed under the skin.