# Hot Math Craft Posts

### Silver & Gold: DIY Modular Origami Christmas Ornaments

After becoming addicted to basic sonobe modular origami, I decided to make ornaments for relatives as Christmas gifts. I tried using fancy paper from stores like Paper Source, and cutting it to proper origami size, but I could never get the tight folds I wanted with non-traditional, non-origami paper. I ended up using this metallic origami paper that folds beautifully, and I'm pretty happy with the tiny models I ended up with. Forgive these pictures (iPhone/Instagram), I don't have my regular...

### How To: Make 6-Sided Kirigami Snowflakes

We've all made them. I remember making hundreds of paper snowflakes when I was in elementary school. You take a piece of paper and fold it in half, then fold it in half again. You now have a piece that is one fourth the size of the original. Now you fold it in half diagonally. You then cut slices out of the edges of the paper, and unfold to find that you have created a snowflake. The resulting snowflake has four lines of symmetry and looks something like this: If you fold it in half diagonall...

### How To: Welcome to Math Craft World! (Bonus: How to Make Your Own Paper Polyhedra)

Welcome to Math Craft World! This community is dedicated to the exploration of mathematically inspired art and architecture through projects, community submissions, and inspirational posts related to the topic at hand. Every week, there will be approximately four posts according to the following schedule:

### Math Craft Monday: Community Submissions (Plus How to Make an Orderly Tangle of Triangles)

It's Monday, which means once again, it's time to highlight some of the recent community submissions posted to the Math Craft corkboard. I also thought that we'd try and create something known as an "Orderly Tangle" or "Polylink".

### How To: Make a Sonobe Jasmine Dodecahedron

Math Craft admin Cory Poole posted instructions on How to Make a Cube, Octahedron & Icosahedron from Sonobe Units, plus some great complex models in his article, How to Make a Truncated Icosahedron, Pentakis Dodecahedron & More. These models use the standard sonobe unit and a coloured variant.

### Math Craft Monday: Community Submissions (Plus Tiling with Coins)

It's Monday, and once again it's time to highlight some of the community submissions posted to the Math Craft corkboard. In addition, I thought we'd take a look at having fun with the geometrical properties of polygons and circles by using one of the best circles I know, the penny.

### How To: Make a Hyperbolic Paraboloid Using Skewers

In Monday's post, we created a sliceform model of a hyperbolic paraboloid. In today's post, we will create a similar model using skewers. The hyperbolic paraboloid is a ruled surface, which means that you can create it using only straight lines even though it is curved. In fact, the hyperbolic paraboloid is doubly ruled and is one of only three curved surfaces than can be created using two distinct lines passing through each point. The others are the hyperboloid and the flat plane.

### News: 7 Templates for Slide-Together Geometric Paper Constructions

The "slide-together" paper construction method is a fun and satisfying way to build 3D geometric objects. It only requires paper, scissors or an exacto knife, and some patience.

### Modular Origami: How to Make a Cube, Octahedron & Icosahedron from Sonobe Units

Modular origami is a technique that can be used to build some pretty interesting and impressive models of mathematical objects. In modular origami, you combine multiple units folded from single pieces of paper into more complicated forms. The Sonobe unit is a simple example unit from modular origami that is both easy to fold and compatible for constructing a large variety of models. Below are a few models that are easy to make using this unit.

### How To: Create Parabolic Curves Using Straight Lines

Curve stitching is a form of string art where smooth curves are created through the use of straight lines. It is taught in many Junior High and High School art classes. I discovered it when my math students started showing me the geometric art they had created.

### How To: Create Concentric Circles, Ellipses, Cardioids & More Using Straight Lines & Circles

Using only a circle and straight lines, it's possible to create various aesthetic curves that combine both art and mathematics. The geometry behind the concentric circle, ellipse, and cardioid dates back centuries and is easily found in the world around us. From an archery target to an apple, can you name these geometric shapes?

### How To: Make the Platonic Solids Out of Playing Cards

Computer Science Professor Francesco De Comité has a fantastic gallery of mathematical images on Flickr. As part of this collection, he has a few hundred images of real or rendered polyhedra made out of paper or playing cards which he calls "slide togethers." These are constructed by making cuts and then sliding one component into the other, creating a shape without using any glue. He constructed the entire set of the platonic solids—the cards form their edges—which can be seen in the image b...

### Modular Origami: Icosahedron, Octahedron & Cube

I spent the holiday weekend becoming fluent in the basics of modular origami. With practice, you can churn out the below models surprisingly quickly.

### Modular Origami: How to Make a Truncated Icosahedron, Pentakis Dodecahedron & More

Last post, the Sonobe unit was introduced as a way to use multiple copies of a simply folded piece of paper to make geometric objects. In this post, we are going to explore that concept further by making two more geometric models. The first is the truncated icosahedron, which is a common stitching pattern for a soccer ball. The second was supposed to be the pentakis dodecahedron, but through systematic errors last night, I actually built a different model based off of the rhombic triacontahed...

### How To: Make Yin-Yang Pillow Boxes

Here's a Math Craft project that takes less than 20 minutes, has an attractive, practical result, and is at least a little mind-blowing due to folding along curves.

### Math Craft Monday: Community Submissions (Plus How to Make a Sliceform Hyperbolic Paraboloid)

It's Monday, which means once again, it's time to highlight some of the most recent community submissions posted to the Math Craft corkboard. I also thought we'd take a look at building a sliceform model of a hyperbolic paraboloid.

### News: Modular Origami

Cory has posted some great picture of Father Magnus' intersecting cubes (the great man is holding one in his right hand) - well the above is what happens when five tetrahedra intersect. It is modular origami and made from just ten sheets of origami paper. technically in a folding sense it is easy - but putting it together is mind-warping

### How To: Carve Polyhedral Pumpkins

Halloween is coming up, so many of you may have a need or desire to carve a pumpkin and turn it into a Jack O' Lantern. This week we are going to explore carving our pumpkins into interesting geometric shapes. In this post, we will carve the pumpkins into spherical versions of polyhedra, and in Thursday's post we will carve 2 dimensional stars and some simple fractal designs into the pumpkins.

### Math Craft Monday: Community Submissions (Plus How to Make a Modular Origami Intersecting Triangles Sculpture)

It's once again Monday, which means it's time to highlight some of the most recent community submissions posted to the Math Craft corkboard. I also thought we'd take a look at building a model that has appeared in numerous posts. It's the simplest of the intersecting plane modular origami sculptures: The WXYZ Intersecting Planes model.

### Holiday Project: Origami Christmas Trees

Thanksgiving. It's sadly over. But happily replaced by the Christmas season!

### News: Math Craft Inspiration of the Week: The Kinetic Wave Sculptures of Reuben Margolin

Reuben Margolin builds large scale kinetic sculptures based off of mechanical waves. Some of his sculptures contain hundreds of pulleys all working in harmony with each other to create sinusoidal waves and their resulting interference patterns. He designs them all on paper and does all of the complicated trigonometric calculations by hand. Everything is mechanical; there are no electronic controllers.

### How To: Fold a Pentakis Dodecahedron

Math Craft admin Cory Poole provided quite a few recipes for sonobe models in his blog, and I followed one to make the pentakis dodecahedron here.

### News: More String Art

I was browsing Reddit.com yesterday and noticed this post. User guyanonymous (yes I am really crediting him regardless of his name!) had posted up this string-art picture which has parabolic curves created from straight lines and gave me permission to post it up here on the corkboard. I love the repeating "flower" pattern.

### News: Math Craft Inspiration of the Week: The Curve-Crease Sculptures of Erik Demaine

Erik Demaine is a Professor of Electronic Engineering and Comp Sci at MI, but he is also an origami folder who has had work displayed at the Museum of Modern Art in NYC. He makes some beautiful models and intricate puzzles, but in my opinion the really inspirational work is the curved creased models. In Erik's own words describing the above models: "Each piece in this series connects together multiple circular pieces of paper (between two and three full circles) to make a large circular ramp ...

### News: DIY Origami Christmas Tree

This is how my version of an origami Christmas tree turned out based on the instructions I posted awhile back. Cory also made a version from white glossy paper, which looks great. I opted for the green and brown look, but it wasn't easy.

### News: Sierpinski Christmas Tree

This three dimensional Sierpinski tetrahedral structure was created with a lot of help from my Year 10, 12 and 13 classes. It is inspired by the Sierpinski triangle fractal.

### News: Making Art with the Golden Ratio

You can do some pretty cool stuff with the golden ratio. The image above is made from taking each quarter-circle in the golden spiral and expanding it into a full circle. In the second image, the spiral and the golden rectangles are overlaid on the the first image, showing how it works.

### How To: Make Icosahedral Planet Ornaments

In honor of the new Astronomy World, I thought we should look at a few planetary icosahedrons. The icosahedron is the most round of the Platonic solids with twenty faces, thus has the smallest dihedral angles. This allows it to unfold into a flat map with a reasonably acceptable amount of distortion. In fact, Buckminster Fuller tried to popularize the polyhedral globe/map concept with his Dymaxion Map.

### Math Craft Monday: Community Submissions (Plus How to Make Mobius Strips)

It's another Monday, which means once again, it's time to highlight some of the recent community submissions posted to the Math Craft corkboard. Additionally, I thought we'd take a look at the Mobius Strip.

### How To: Make Torus Knots from Soft Metals

Torus knots are beautiful knots formed by wrapping a line around a torus and tying the ends together to form a loop. The resulting knot has a star-like appearance when viewed from above. The 36 examples with the least number of crossings can be seen at the Knot Atlas's page on torus knots.

### News: Origami Valentine's Day Present

I made a Origami Valentine's day present for my Little Sister and Neice using heart and rose origami patterns I found on-line and put them in a backet with heart shaped lollipop I bought from Target.

### How To: Make Nested Cube and Octahedron Boxes

These boxes are inspired by a comment from Imaatfal Avidya on a corkboard post on Platonic polyhedra from sonobe units. Imaatfal was commenting about how the cube and octahedron are related to each other.

### News: 180 Unit Sonobe Buckyball

I wondered how silly you could get with sonobe, and had a bash at a buckyball, which is a fullerene (technically a truncated isocahedron; you can see a simple model here). It's twelve pentagons—each surrounded by 5 hexagons (20 in total)—making a football shape in England or a soccer ball shape in the USA.

### News: The Unreasonable Beauty of Mathematics

Back in August, Scientific American posted a slideshow fitting for Math Craft. Click through to check out a slideshow depicting beauty found in mathematical structures—including a beautiful knot theory chart befitting of this week's project.

### News: Origami Sierpinski Tetrahedron Constructed with 250+ Modules

I've already posted a brief roundup of interesting models folded by Michal Kosmulski, expert orgami-ist and IT director at NetSprint. However, I didn't include my favorite model, because I felt it deserved its own post. Kosmulski folded an elaborate and large Sierpinski tetrahedron, which he deems "level 3" in difficulty. (Translation: hard). It is constructed with 128 modules and 126 links, based on Nick Robinson's trimodule.

### How To: Make a 'Flex Mex'—A Mathematically Delicious Hexaflexagon Burrito

Here's a great excuse to play with your food—and learn some math while you're at it. We've all seen a hexaflexagon folded out of paper, but how about a burrito? Vi Hart, a "mathmusician" over at the Khan Academy, came up with the Flex Mex, a burrito folded into a hexaflexagon with all the toppings inside. The spreadable ingredients (guacamole, sour cream and salsa) go inside the folds, then it's topped with beans and cheese.

### How To: Design Your Own Playing Card Sculpture

Download the Software Go to the Antiprism downloads page. Download and install Antiprism 0.20.

### Mathematical Holiday Ornaments: Escher "Snow Flakes"

This week's post on creating 6-sided Kirigami Snowflakes got me interested in seeing whether I could use the process to create tessellation snowflakes using the method. I still haven't succeeded, but I did decide to make some ornaments based off a few of the tessellations by M.C. Escher that have a 6 sided symmetry.

### News: DIY Crazy Paper Toy

This is just too cool. As soon as I saw this, I thought, "Math Craft!"

### News: 30 Square Sliding Modular Origami

Cory's post with instructions and templates Here's my first attempt at the 30 squares model. I needed to be a little bit more careful in the measuring and cutting as not everything matches up - but it is still a really pleasing shape.