Boxi Learn › Computing › Stage 1 · Observe and Say
Send a picture with a few numbers
CS-3 Any information can become numbersCS-1 Break a big job into small stepsX-1 Guess, then check
What many people think
Making a picture file smaller always loses some of the picture.
The idea
A black-and-white picture can be sent as counts of same-colour squares in a row, so a picture with long runs needs far fewer numbers and still comes back exactly the same.
Explain it
Read the numbers for one heart row to a friend who can't see it. Why can they colour exactly the same row? Why does a checkerboard need more numbers?
Try at home
On squared paper, colour a simple 10 × 10 picture. Read only the row numbers to someone at home and let them colour their own grid. Hold the two papers side by side: are they the same?