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MAA is an **official** partner of the second USA Science & Engineering Festival. The culminating event is the USA Science & Engineering Festival Expo and Book Fair.

Walter E. Washington Convention Center

801 Mt Vernon Pl NW, Washington, D.C. 20001

Saturday, April 28, 2012, 10 a.m.-6 p.m.

Sunday, April 29, 2012, 10 a.m.-4 p.m.

The MAA booth, under the banner “Math Is Everywhere”, featured A Mathematical Petting Zoo, a slideshow of MAA Found Math, our member-generated gallery of photos of math in the real world, and "Are You Smarter Than an 8th Grader in Math?", an interactive quiz based on the AMC 8 contest. Copies of the Field Guide to Math on the National Mall were also available.

What does math feel like? Sample an array of intriguing mathematical forms.

*Hyperbolic Quilt*

This unruly quilt, made up of regular pentagons stitched together so that four pentagons meet at each corner, will not lie flat. It can be thought of as a piece of the hyperbolic plane, an infinite, two-dimensional mathematical surface.

*Triply Twisted Deltoid Torus*

The ring-shaped, three-dimensional form is known mathematically as a torus (akin to the surface of a doughnut). In this case, it has a cross section described as a deltoid curve: a hypocycloid of three cusps. It is the curve that results from the path of a point on the circumference of a circle as it rolls without slipping along the inside of a circle with three times its radius. The triangular cross section twists through 360 degrees as it completes the circuit to form this triply twisted surface.

*Figure-Eight Knot*

A mathematical knot is a closed curve that loops through three-dimensional space and cannot be untangled to form a simple loop (unknot). Though often presented as a two-dimensional knot diagram, a knot is a three-dimensional object and can be modeled from copper tubing. Such a knot has no preferred top, bottom, front, or back. And it can look completely different when viewed from different directions. One fundamental problem in knot mathematics concerns ways to distinguish one knotted form from another.

*Temari Ball * with Cuboctahedral Symmetry

Temari is a folk art form that originated in China and was later introduced to Japan. A Temari ball is constructed from a spherical core wrapped in yarn, then decorated with colored threads to create geometrical patterns on its surface. This example can be described as having octahedral symmetry and cuboctahedral symmetry.

*Fortunatus's Purse*

According to legend, the purse of Fortunatus continually replenished itself as coins were withdrawn from it. A story by Lewis Carroll (Charles L. Dodgson) describes how to make such a purse from four handkerchiefs. The resulting form is a model of a topological structure known as the projective plane. A projective plane can be constructed by gluing both pairs of opposite edges of a rectangle together giving both pairs a half-twist. It is a one-sided surface, but cannot be realized in three-dimensional space without crossing itself.

*Seven-Color Torus*

The Four-Color Theorem states that any map drawn on a flat surface (Euclidean plane) or on a sphere can be colored using only four colors in such a way that no two adjacent countries are the same color. A map on the surface of a torus (a doughnut-shaped surface) would require seven colors.

*Möbius Scarf*

A Möbius strip is a one-sided, one-edged surface. You can make one by giving a strip of paper a half-twist, the taping the ends together. The scarf is knitted so that it forms a loop with one continuous surface.

*Klein Bottle* (Nancy Shaw)

In 1862, mathematician Felix Klein imagined sewing together two Möbius strips to create a single-sided bottle with no edge. Its inside is its outside, so it has no volume. A true Klein bottle needs four dimensions for the surface to pass through itself without a hole. While it cannot be embedded in three dimensions, you can immerse it in three dimensions and represent it in plastic by stretching the neck of the bottle through its side and joining its end to a hole in the base.

*1-2 Icosahedron*

The icosahedron is one of the five Platonic solids. Its twenty faces are equilateral triangles, with five meeting at each corner. In this model, each face is further divided into six congruent 30-60-90 triangles, for a total of 120 triangles. The model is constructed from 15 slotted rings lying in 15 planes.

See the many ways in which mathematics can manifest itself, in streetscapes, natural settings, artworks, architectural structures, and more.

The MAA website features a new math-related photo every week. Introduced in 2007, MAA Found Math has grown into a large trove of stunning images, submitted by MAA members and many others. The MAA Found Math slideshow presents a noteworthy selection of these images. Explore the full collection of MAA Found Math on maa.org/FoundMath/.

See math around you? Submit your photos with your name and a brief description to Laura McHugh at editor@maa.org.

Match wits with 8th-grade students by answering questions from the AMC 8 mathematics contest.

More than 150,000 students across the country compete each year in the American Mathematics Competitions (AMC 8), organized by the Mathematical Association of America. The AMC 8 is a 25-question, 40-minute, multiple-choice test in middle-school mathematics to promote problem-solving skills. Problems not only range from easy to difficult but also cover a wide range of applications of mathematics.

Sample question:

*Twelve friends met for dinner at Oscar's Overstuffed Oyster House, and each ordered one meal. The portions were so large there was enough food for 18 people. If they share, how many meals should they have ordered to have just enough food for the 12 of them?*

(A) 8 | (B) 9 | (C) 10 | (D) 15 | (E) 18 |

You can find more questions at MAA MinuteMath.

The world around us is rich with mathematical wonder. The MAA has developed a field guide to highlight the mathematical aspects of a dozen sights at or near the National Mall in Washington, D.C. Start your mathematical treasure hunt among the monuments, museums, and fields at the heart of the nation's capital by downloading the field guide here (pdf) or picking up a copy at the MAA booth during the Expo on Oct. 23-24, 2010. Check out the Field Guide's Official Page for additional information.

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4482

News Date:

Thursday, October 18, 2012