While leafing through a few recent issues of New York Times Magazine I bumped into a few spectacular photographs of some plaster forms. It?s hard to imagine that those structures were originally used to teach advanced students trigonometry.

Called stereometric models, they were built by some highly enterprising maths teachers a century ago in Germany to help scholars grasp complex mathematical formulas. Last year, the Japanese photographer Hiroshi Sugimoto shot each object, the tallest of which is less than a foot high, from below at close range so that they appeared monumental. The series of photographs, Mathematical Forms, reimagine these scientific models as things of wonder. They signify Sugimoto?s belief that art is possible even without artistic intention.

PUZZLE 1: One of the methods used to encrypt a message is to use the message itself. We begin by providing a secret number that is used for the offset of the first letter and is known only to sender and receiver.

This starting value is called a seed. For example, if we encode the word CAT, we begin by finding the alphabetic value of each letter: 3, 1 and 20; and then use the value of the previous letter as an offset, with the first letter using the seed value.

Suppose the seed is 5:

C (3) ? (3 + 5[seed] = 8) H

A (1) ? (1 + 3[1st letter] = 4) D

T (20) ? (20 + 1[2nd letter] = 21) U

So the encoded message is HDU. It should be clear how, using the seed 5, it is possible to decode it easily.

However, your task is to decode the following message without being told the seed:

X B M W W N B G C U A M W N W H C V R Y L S W A Q

Solutions on March 14

CORRECT ENTRIES

February 14

Debabrata Sengupta, Dum Dum; Mr. B. D. Mundhra, Cal - 31; Abhigyan Mundhra, Apeejay School;Sandeep Jain, Dimapur;Rima Das, NIT-Belgharia; Utsav Kundu,Poddar Institute of Management & Technology; Anirban Basumallik,DBPC; Arun Kumar Chattopadhyay, Cal-29; Satadal Chatterjee, Cal-56; Subhash Chandra Modak, Halisahar; Subhasini Sarkar, Dum Dum Park; Rammanohar Agarwal, Jharia; R.N. Chattopadhyay, Siliguri

CORRECT ENTRIES

February 7

Sushil Kumar Roy, Cal-36; Anuradha Srivastava, Jamshedpur; P.K. Iyengar, Asansole; Dhruba Mohanty, Bhubaneswar; A.K. Singhania, Purulia; Narendra Agarwal, Gangtok

Please send your entries to knowhow@abpmail.com within 10 days. Post snail-mail entries addressed to KnowHOW, The Telegraph, Prafulla Sarkar Street, Calcutta- 70001. Mention the date of puzzle clearly.

PUZZLE CRACKED

Solution 1: It seems that it?s an island in the Dead Sea. Just as due to excessive salt in a waterbody, people float on the surface without getting drowned, the man must have made his way back to the nearest land floating. It doesn?t matter at all whether he can swim or not.

Solution 2: Both Sam and Adam are lawyers. Explanation: If Sam would have been an accountant, he couldn?t have declared himself to be a lawyer. Hence, Sam is definitely a lawyer. Moreover, since he always lies about something, his comment on Adam?s profession must be a lie (if the earlier statement is true). In that event, Adam must be a lawyer, not an accountant

Solution 3: Tom ate SANDWICH for his lunch, which is obvious from the first letters of each word: Sausages And Noodles Drenched With Ice Cream, Hashed.