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# kryptos

In 1988, as a new headquarters for the American Central Intelligence Agency (CIA) was being built in Langley, Virgina, sculptor Jim Sanborn was commissioned to create artwork for the courtyard of the new building. In 1999, a computer scientist named Jim Gillogly announced that he had solved most of the puzzle. There were four distinct […]

# Latin square

The “Gamma plus two” method for generating “odd order” magic squares, the“Gamma plus two plus swap” method for generating “singly even order” magicsquares, and Durer’s method for generating “doubly even order” magic squares. By Professor Edward Brumgnach, P.E. City University of New YorkQueensborough Community College In combinatorics and in experimental design, a Latin square is […]

# N-Queens

Construct a magic square nxn (using the numbers 1 to n2) and place n queens only on these cells which contain prime numbers, such that no queen can take any other queen. 1. What is the smallest magic square (n) having solution? 2. Get one solution for the next three larger magic squares (n+1, n+2 […]

# Adventures in Group Theory

Adventures in Group Theory: Rubik’s Cube, Merlin’s Machine, and Other Mathematical Toys David Joyner 5-15-2008 Published on Jan 15, 2016 The vast majority of people who tackle the Rubik’s cube never succeed in solving it without looking up somebody else’s solution. In this video the Mathologer reveals a simple insight that will enable all those […]

# Lines

Construct nine triangles by drawing three straight lines through a capital M Starting with a pentagram, using only two additional straight lines, construct ten disjoint triangles You just bought TEN trees: Plant them in FIVE rows with FOUR trees in each row Advertisements

# pentomino

Pentominoes Pentominoes: Puzzles & Solutions PENTOMINOES – An Introduction A pentomino is a plane geometric figure formed by joining five equal squares edge to edge. It is a polyomino with five cells. There are twelve pentominoes, not counting rotations and reflections as distinct. They are used chiefly in recreational mathematics for puzzles and problems.[1] Pentominoes […]

# Soma cube

The Soma cube is a solid dissection puzzle invented by Piet Hein in 1933[1] during a lecture on quantum mechanics conducted by Werner Heisenberg. Seven pieces made out of unit cubes must be assembled into a 3×3×3 cube. The pieces can also be used to make a variety of other 3D shapes. The pieces of […]

# seven red lines

Published on May 5, 2014 How to draw seven red lines, all perpendicular, some with green ink, some with transparent ink, and one in the form of a kitten. This is a caricature but experienced engineers do not behave like this. Users NEVER know with precision what they want and it is the job of […]

# The 7.11 problem

A man goes into a store and selects four items to purchase. He walks up to the counter to pay and the clerk says “Hold on, my cash register is broken, so I have to use a calculator to get your total… okay, that’ll be $7.11” The man pays, and as he is walking out, […]