A word triangle is created by taking a word, putting the first letter on the first line, putting two of the second letter on the next line, three of the third letter on the third line, etc. Given the word TEASER, the word triangle would look like this:
T
EE
AAA
SSSS
EEEEE
RRRRRR
If you begin at the top and start spelling TEASER by either moving to the letter directly below the letter you are currently on or by moving to the letter that is immediately to the right of the letter below the letter you are currently on, you could use several different paths to spell the word. For instance, if your path takes you to the third ‘A’ you could either go to the third ‘S’ or the fourth ‘S’, but not to the first or second ‘S’.
Can you determine how many possible paths there are for this word triangle? How about for word triangles with the words of different lengths?
Answer
2^5 = 32
For any word of given length, L, the number of paths, P, can be found by P = 2^(L-1).
This is essentially Pascal’s Triangle. Usually, these are seen as more of the shape of a pyramid, but since spacing can’t be done consistently, the teaser had to limit the paths either to the letter below the current letter or the letter below and to the right of the current letter.