# Corinna Beuermann-Kulp

Grundschule Friedland (Elementary School Friedland Germany)
37133 Friedland, Landkreis Göttingen, Niedersachsen, Germany

I work at the elementary school in Friedland and create and sew unique mathematical geometrical toys for children 5 years old and older. Together with the mathematical institute of the university in Göttingen, I developed the "Kindergarten Koffer" - a suitcase with different Puzzles: 8 mathemagic cubes, 1 Pentomino, 1 Sudoko, the magnetic dodecagon with 60 pieces and the Maths Pie. I made many spheres with different tilings on the surface, and 18 edge models from polyhedra. My hobby is sewing stellated polyhedra, quilts and other robust, elastic, haptic and soft toys/puzzles!
My circular quilt: "Da staunst Du - 29 Bauklötze!" was shown in the exhibit for mathematical quilts in different locations in Germany during the year of math in 2008.

Modular edge models of poyhedra. Example: Rhombic triacontahedron
25 x 25 x 25 cm
Cotton fabric, thread, little styrofoam balls.
2011

One of 18 different modular edge models of polyhedra.
The material is very haptic, sturdy and very well suited for curious kids, but they should not give this toy to their pet, because it is filled with rustling styrofoam balls.
On the surface of the polyhedron you can discover triangles, tetragons, pentagons and hexagons. These can be folded toward the center or the outside, thereby changing the appearance and the stability of the polyhedron. The models are also sporty: You can throw and catch them well. A balloon in the middle will change the flight trajectory and stability.
Count the polygonal faces, straight edges and vertices to discover Eulers characteristic and make your math teacher happy! Because each model is different.

Das magnetische Zwölfeck. The magnetic Dodecagon.
58 x 58 x 1 cm
Round metal plate, 60 extrastrong magnets, Cotton fabric, thread, strong felt
2009

The magnetic dodecagon is very robust and very suitable for curious children, but they must not swallow the 60 extra strong magnets.
One basic concept of school geometry is symmetry. On the one hand there is the property of symmetry of figures and objects, on the other hand there are symmetry maps (mirroring, rotation), which produce regularity. This dodecagon consists of 24 small and 24 large diamonds and 12 squares with complementary colors on their front and back. The edge lengths are all equal, the angles are 30 ° / 150 °, 60 ° / 120 °, 90 ° / 90 °. From the 60 pieces you can produce one large or 4 small dodecagons. There are many possible arrangements for their colors! Comprehend maths with head, heart and hand. I like puzzles!