Everyday Life is Full of Math

Jun Mitani is a professor of Information and Systems at University of Tsukuba, JAPAN. He received his Ph.D. in engineering from the University of Tokyo in 2004. He has been present post since April 2015. His research interests center on computer graphics, particularly geometric modeling techniques and their application to origami design. The origami artworks created by him have features that are three-dimensional shapes with smooth curved surfaces. His main books are “3D Origami Art (2016)” and “Curved-Folding Origami Design (2019)”. His unique origami has been well received around the world and he had received invitations to hold workshops and exhibitions in Germany, Switzerland, Italy, Israel and many other countries. His work had inspired the design of the trophy for the Player of the Match winner of each game at the Rugby World Cup 2019. He was appointed as a Japan Cultural Envoy from the Agency for Cultural Affairs and traveled to eight Asian countries to promote cultural exchanges through origami in 2019. In 2024, he was appointed as the official ambassador for the 65th anniversary of Plarail (a model train toy by Takara Tomy).

• Foreword Preface Section I TheWonders of Numbers and Shapes Around Us Chapter 1 Is “Paper” the Ultimate Strategy in a Rock-Paper-Scissors Tournament!? Chapter 2 Math Magic with Tricks and Twists Chapter 3 The Numbers Around Us: Which Digit is Used the Most? Chapter 4 Conic Sections Created by Light Chapter 5 What Is the True Shape of a Crescent Moon Chapter 6 An Equation That Draws the Shape of a Pon de Ring Donut Chapter 7 The Method is Wrong, but the Result is Correct Chapter 8 A Mathematical Mystery! The Collatz Conjecture Chapter 9 Strange Magic Square Chapter 10 Rings That Look Different but Have the Same Volume Chapter 11 Convex Polygons and Radar Charts Chapter 12 What If We Used Dice to Decide How Much NewYear’s Money to Give? Chapter 13 Shapes Made with Triangles Chapter 14 Success Rate of the “Kendama” Challenge Chapter 15 Estimating the Dimensions of a 1-Liter Milk Carton Chapter 16 Seats on the Shinkansen (Japan’s bullet train) Divided into Two and Three Rows Section II Playful Math You Can Touch and Feel Chapter 17 Enjoying the Cleanup of Building Blocks Chapter 18 The Mysterious Surface Made of Cotton Swabs: A Hyperboloid Chapter 19 With 30 Toy Train Tracks, You Can Play for Over 200 Years Chapter 20 Is It Easy or Difficult to Make a Plarail Layout That Loops Back to the Start? Chapter 21 Looking at Pi Chapter 22 The Tower of Hanoi Algorithm Chapter 23 Folding Paper Along Curves Is Fun Chapter 24 Folding Paper to Reach the Moon Chapter 25 The Wonder of Repeated Folding Chapter 26 Modular Origami Balls and Polyhedral Duals Chapter 27 Pop-Up Figures Chapter 28 The Shape of a Peel Spun from an Apple Chapter 29 Fractal Figures Drawn by Coloring Grid Cells Chapter 30 A Rather Casually Made Star Polyhedron Chapter 31 The Wonder of Origami Crease Patterns Chapter 32 How Can We Fit As Much As Possible into an Envelope? Chapter 33 Spiral Made from Paper Tape Afterword