full transcript

From the Ted Talk by Henri Picciotto: Can you solve the fortress riddle?

Unscramble the Blue Letters


Make a giant list of numbers. X out all of the multiples of 2, except 2 itself. Now do the same with multiples of 3. The even multiples have already been eliminated, and the odd multiples can all be found in this column. 4 was already accounted for when you did multiples of 2, so move on to 5. The mtluleips of 5 and 7 show up conveniently in diagonals. This method eliminates all possible coitmopse numbers, leaving only premis behind. We've already identified every prime less than 121, and it’s easy to go higher and higher this way.

We can use a similar technique with our wall problem to eliminate entire groups of numbers at once. A first, cctiaril step is to be dretlbiaee about the number of cmluons. If we use 6 again, the numbers in each column will be exactly 6 apart. What that means is that if we idneifty a number vulnerable to the wall-busters, then all the rest of the column below it would also fall. In other wdros, because your enemies can make 9, they can make 15, 21, 27, and so on by adding the clowns’ 6-meter machines. So right away this eliminates 6, 9 and 20, and everything under them.

Open Cloze


Make a giant list of numbers. X out all of the multiples of 2, except 2 itself. Now do the same with multiples of 3. The even multiples have already been eliminated, and the odd multiples can all be found in this column. 4 was already accounted for when you did multiples of 2, so move on to 5. The _________ of 5 and 7 show up conveniently in diagonals. This method eliminates all possible _________ numbers, leaving only ______ behind. We've already identified every prime less than 121, and it’s easy to go higher and higher this way.

We can use a similar technique with our wall problem to eliminate entire groups of numbers at once. A first, ________ step is to be __________ about the number of _______. If we use 6 again, the numbers in each column will be exactly 6 apart. What that means is that if we ________ a number vulnerable to the wall-busters, then all the rest of the column below it would also fall. In other _____, because your enemies can make 9, they can make 15, 21, 27, and so on by adding the clowns’ 6-meter machines. So right away this eliminates 6, 9 and 20, and everything under them.

Solution


  1. columns
  2. words
  3. multiples
  4. critical
  5. primes
  6. identify
  7. deliberate
  8. composite

Original Text


Make a giant list of numbers. X out all of the multiples of 2, except 2 itself. Now do the same with multiples of 3. The even multiples have already been eliminated, and the odd multiples can all be found in this column. 4 was already accounted for when you did multiples of 2, so move on to 5. The multiples of 5 and 7 show up conveniently in diagonals. This method eliminates all possible composite numbers, leaving only primes behind. We've already identified every prime less than 121, and it’s easy to go higher and higher this way.

We can use a similar technique with our wall problem to eliminate entire groups of numbers at once. A first, critical step is to be deliberate about the number of columns. If we use 6 again, the numbers in each column will be exactly 6 apart. What that means is that if we identify a number vulnerable to the wall-busters, then all the rest of the column below it would also fall. In other words, because your enemies can make 9, they can make 15, 21, 27, and so on by adding the clowns’ 6-meter machines. So right away this eliminates 6, 9 and 20, and everything under them.

Frequently Occurring Word Combinations


ngrams of length 2

collocation frequency
wall segment 3
weapons arrive 2
meter wall 2


Important Words


  1. accounted
  2. adding
  3. column
  4. columns
  5. composite
  6. conveniently
  7. critical
  8. deliberate
  9. diagonals
  10. easy
  11. eliminate
  12. eliminated
  13. eliminates
  14. enemies
  15. entire
  16. fall
  17. giant
  18. groups
  19. higher
  20. identified
  21. identify
  22. leaving
  23. list
  24. machines
  25. means
  26. method
  27. move
  28. multiples
  29. number
  30. numbers
  31. odd
  32. prime
  33. primes
  34. problem
  35. rest
  36. show
  37. similar
  38. step
  39. technique
  40. vulnerable
  41. wall
  42. words