Chronology of Updates
Note
I have placed chronology of updates for 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 and 2004 into separate files. Starting with 1997, the most recent entries appear topmost. Besides providing an insight of this site's evolution, chronology updates may be used for word searches.
| December 31, 2005 |
Pascal in a Cyclic Quadrilateral |
| December 30, 2005 |
Orthologic Triangles in a Quadrilateral |
| December 29, 2005 |
All Triangles Are Isosceles |
| December 28, 2005 |
Pedal Triangle and Isogonal Conjugacy |
| December 26, 2005 |
Complex Numbers: A Dynamic Tool |
| December 25, 2005 |
Carpets in a Parallelogram |
| December 24, 2005 |
Two Rectangles in a Rectangle |
| December 24, 2005 |
More Bottles in a Wine Rack |
| December 23, 2005 |
A Property of Rhombi |
| December 23, 2005 |
Circle-Stacking Theorem |
| December 22, 2005 |
Gergonne and Medial Triangles Are Orthologic |
| December 21, 2005 |
Cartesian Coordinate System |
| December 18, 2005 |
Common Tangents to Two Circles II |
| December 17, 2005 |
Bottles in a Wine Rack |
| December 16, 2005 |
Isosceles on the Sides of a Triangle |
| December 15, 2005 |
Self-descriptive Strings |
| December 14, 2005 |
3-Term Arithmetic Progression |
| December 12, 2005 |
Variations on the Theme of Tremas II |
| December 10, 2005 |
Listing All Permutations: Johnson-Trotter Method |
| December 9, 2005 |
Dominoes on a Chessboard |
| December 7, 2005 |
Party Acquaintances |
| December 5, 2005 |
Common Tangents to Two Circles I |
| November 27, 2005 |
Straight Tromino on a Chessboard |
| November 22, 2005 |
Eight Digits Puzzle |
| November 20, 2005 |
Square From Nowhere |
| November 18, 2005 |
Parallel Chords |
| November 17, 2005 |
Variations on the Theme of Tremas |
| November 15, 2005 |
Counting Triangles II |
| November 14, 2005 |
Carpet With a Hole |
| November 13, 2005 |
Carpets Theorem With Parallelograms |
| November 12, 2005 |
Six Incircles in an Equilateral Triangle |
| November 11, 2005 |
Equidecomposition of Two Rectangles |
| November 10, 2005 |
Perigal's Proof of the Pythagorean Proposition |
| November 4, 2005 |
Equidecomposition of Two Parallelograms |
| November 3, 2005 |
100 Prisoners and a Light Bulb by Stuart Anderson |
| November 3, 2005 |
The Carpets Theorem |
| November 2, 2005 |
Wallace-Bolyai-Gerwien Theorem |
| November 1, 2005 |
Equidecomposition of a Rectangle and a Square |
| October 31, 2005 |
Equidecomposition of a Triangle and a Rectangle |
| October 31, 2005 |
The Chaos Game: Address Space vs IFS |
| October 30, 2005 |
Sierpinski Gasket By Common Trema Removal |
| October 29, 2005 |
Inequality (1 + 1-3)(1 + 2-3)(1 + 3-3)...(1 + n-3) < 3 |
| October 28, 2005 |
A Property of Equiangular Polygons |
| October 27, 2005 |
Sierpinski Gasket Via Chaos Game |
| October 15, 2005 |
Who Needs Monty? |
| October 10, 2005 |
Upgraded the Y Can't End in a Draw page |
| October 5, 2005 |
The Lepidoptera of the Quadrilateral |
| October 4, 2005 |
Y Can't End in a Draw |
| September 28, 2005 |
Haruki's Theorem |
| September 27, 2005 |
Fixed Point of Circles Orthogonal to the Given One |
| September 26, 2005 |
Mirror property of the altitudes |
| September 25, 2005 |
Hiroshi Haruki's Lemma |
| September 22, 2005 |
The Two Men of Tibet |
| September 19, 2005 |
Mathematicians Doze Off |
| September 19, 2005 |
The Affirmative Action Problem |
| September 18, 2005 |
A Circle With Two Centers |
| September 16, 2005 |
Two Perpendiculars From a Point to a Line |
| September 16, 2005 |
Desargues in the Bride's Chair (with Pythagoras) |
| September 15, 2005 |
Dividing a Segment by Paper Folding |
| September 15, 2005 |
Integers and Rectangles: Two Simple Proofs |
| September 14, 2005 |
Three Tangents, Three Secants |
| September 13, 2005 |
Area of Median Triangle |
| September 12, 2005 |
Solitaire in Two Colors |
| September 10, 2005 |
Loop or Halt |
| September 9, 2005 |
A Maimed Cake |
| September 8, 2005 |
Euclid I.43 |
| September 7, 2005 |
Fractions on a Binary Tree II |
| September 4, 2005 |
Archimedes' Quadruplets |
| August 17, 2005 |
The Symmedians |
| August 15, 2005 |
Bisectal Circle |
| August 11, 2005 |
Three Tangent Circles |
| August 10, 2005 |
Ceva and Menelaus Meet on the Roads |
| August 9, 2005 |
Fermat's Point |
| August 3, 2005 |
Malfatti's Problem, Hart's Solution |
| July 29, 2005 |
Properties of the Circle of Similitude |
| July 27, 2005 |
Circle of Similitude |
| July 26, 2005 |
Malfatti's Problem |
| July 25, 2005 |
Internal Tangents to Three Circles |
| July 24, 2005 |
Inscriptible and Exscriptible Quadrilaterals |
| July 22, 2005 |
Four Pegs That Form a Square |
| July 20, 2005 |
A solution to the four travelers problem |
| July 16, 2005 |
Two Colors in Two Rows II |
| July 16, 2005 |
Two Colors in Two Rows |
| July 15, 2005 |
Inequality 1/2·3/4·5/6· ... ·99/100 < 1/10 |
| July 14, 2005 |
Life-like Automaton With Definable Rules |
| July 14, 2005 |
The Game of Life |
| July 13, 2005 |
On Bottema's Shoulders II |
| July 12, 2005 |
On Bottema's Shoulders |
| July 10, 2005 |
Simple Cellular Automaton |
| July 9, 2005 |
Weighing 12 coins |
| July 8, 2005 |
Integer Rectangle on a Chessboard by N. Bowler |
| July 7, 2005 |
Pole and Polar with respect to a Triangle |
| July 6, 2005 |
Pythagorean Theorem By Plane Tessellation |
| July 5, 2005 |
Three Tangents II |
| July 4, 2005 |
See-Saw Lemma |
| July 3, 2005 |
Birds on a Wire by S. Anderson |
| July 2, 2005 |
Concurrency in the Intouch Triangle |
| July 1, 2005 |
Dissection of a Rectangle into Two Chessboards |
| June 25, 2005 |
Proof #54 of the Pythagorean theorem |
| June 24, 2005 |
A Neglected Pythagorean-Like Formula |
| June 19, 2005 |
Minimax Theorem |
| June 18, 2005 |
A Versatile Theorem |
| June 14, 2005 |
Cube Counting Ambiguity |
| June 12, 2005 |
Shifting Cube Illusion |
| June 11, 2005 |
Viviani's theorem II |
| June 10, 2005 |
Integers and Rectangles: a Proof by Induction |
| June 8, 2005 |
Integers and Rectangles |
| June 7, 2005 |
Proof #51 of the Pythagorean theorem |
| June 5, 2005 |
Hart's Inversor |
| June 2, 2005 |
Hart Circle |
| June 1, 2005 |
Polar Circle |
| June 1, 2005 |
Four Triangles, One Circle |
| May 30, 2005 |
Feuerbach's Theorem: A Proof |
| May 29, 2005 |
Incidence in Feuerbach's Theorem |
| May 28, 2005 |
Rectangle on a Chessboard |
| May 26, 2005 |
Proofs #49 and #50 of the Pythagorean theorem |
| May 25, 2005 |
Proofs #46, #47 and #48 of the Pythagorean theorem |
| May 24, 2005 |
3-Colors Tower of Hanoi |
| May 23, 2005 |
Hanoing |
| May 22, 2005 |
Shepard's Parallelogram Illusion |
| May 21, 2005 |
Parallelogram Illusion |
| May 20, 2005 |
Plane Isometries |
| May 19, 2005 |
Simple Quadrilaterals Tessellate the Plane |
| May 18, 2005 |
Glide Reflection |
| May 17, 2005 |
Rotation Transform |
| May 16, 2005 |
Homothety |
| May 15, 2005 |
Nagel Line |
| May 12, 2005 |
Coaxal Circles Theorem |
| May 11, 2005 |
Apollonian Circles Theorem |
| May 8, 2005 |
Hex Can't End in a Draw |
| May 5, 2005 |
Another Pair of Twins in an Arbelos |
| May 5, 2005 |
Divide a Circle into N Parts of Equal Area |
| May 4, 2005 |
Lost Boarding Pass |
| May 3, 2005 |
Area of Arbelos |
| May 3, 2005 |
Light Bulbs in a Circle |
| May 1, 2005 |
Translation Transform |
| April 30, 2005 |
Reflection In Line |
| April 29, 2005 |
Secant Angles |
| April 27, 2005 |
Sieve of Squares |
| April 26, 2005 |
Sieve of Eratosthenes |
| April 22, 2005 |
Nagel Point of Medial Triangle |
| April 21, 2005 |
An Interesting Number |
| April 21, 2005 |
Locus of Points in a Given Ratio to Two Points |
| April 20, 2005 |
External Angle Bisector |
| April 20, 2005 |
Tangency Point of Two Circles |
| April 19, 2005 |
Property of Angle Bisectors II |
| April 19, 2005 |
Property of Angle Bisectors |
| April 18, 2005 |
Adams' Circle |
| April 17, 2005 |
Inscribed Angles |
| April 16, 2005 |
Inscribed and Central Angles in a Circle |
| April 15, 2005 |
Divisibility by 7, 11, and 13 |
| April 14, 2005 |
Inflection Points of Fourth Degree Polynomials |
| April 12, 2005 |
Munching on Circles |
| April 10, 2005 |
Signs in a Matrix |
| April 8, 2005 |
Partitioning 3-Space with Circles |
| April 7, 2005 |
Maximum Volume of a Cut Off Box |
| April 2, 2005 |
A Sticky Problem |
| March 30, 2005 |
Angle Trisection by Hippocrates |
| March 30, 2005 |
Rotating Gears |
| March 30, 2005 |
Morphing |
| March 29, 2005 |
Concurrency in Arbelos |
| March 28, 2005 |
Structural Constellation |
| March 27, 2005 |
Archimedes' Twin Circles and a Brother |
| March 26, 2005 |
Concyclic Points in Arbelos |
| March 21, 2005 |
Problem of Equal Steps II |
| March 20, 2005 |
Problem of Equal Steps |
| March 19, 2005 |
Gothic Arc |
| March 18, 2005 |
Book of Lemmas: Proposition 15 |
| March 17, 2005 |
Book of Lemmas: Proposition 13 |
| March 17, 2005 |
Book of Lemmas: Proposition 12 |
| March 16, 2005 |
Book of Lemmas: Proposition 10 |
| March 16, 2005 |
Two Butterflies Theorem III |
| March 15, 2005 |
Two Butterflies Theorem II |
| March 15, 2005 |
Book of Lemmas: Proposition 6 |
| March 14, 2005 |
Book of Lemmas: Proposition 5 |
| March 13, 2005 |
Book of Lemmas: Proposition 3 |
| March 13, 2005 |
Book of Lemmas: Proposition 2 |
| March 12, 2005 |
Book of Lemmas: Proposition 1 |
| March 11, 2005 |
Rectangle in Arbelos |
| March 9, 2005 |
4×4×4 Tic Tac Toe |
| March 7, 2005 |
What Is Arithmetic? |
| March 5, 2005 |
Hummer's Mind Reader |
| March 3, 2005 |
Proof #45 of the Pythagorean theorem |
| March 2, 2005 |
Coin Game |
| February 22, 2005 |
What Is Geometry? |
| February 10, 2005 |
Staircase Illusion |
| February 9, 2005 |
Poggendorff's Illusion |
| February 9, 2005 |
Wundt Block Illusion |
| February 8, 2005 |
Wundt Illusion |
| January 31, 2005 |
Dividing a Segment into N parts: Besteman's Construction II |
| January 31, 2005 |
Dividing a Segment into N parts: Besteman's Construction |
| January 30, 2005 |
Dividing a Segment into N parts: GLaD Construction |
| January 29, 2005 |
Dividing a Segment into N parts: SaRD Construction |
| January 7, 2005 |
Problem in an Equilateral Triangle II |
| January 6, 2005 |
Property of the Powers of 2 |
| January 4, 2005 |
Problem in an Equilateral Triangle |
Copyright © 1996-2009 Alexander Bogomolny
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