Tag: icosahedron

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July Newsletter: Rainbow Icosahedron

Four Icosahedra and a Pentagon Bowl sitting on a white plastic board. One Icosahedron is totally clear. Two Icosahedron are heavily colored with transparent primary or secondary colors. The last Icosahedron is thinly colored with a washy effect. A clear pentagon bowl sits adjacent.

It’s Summer!  Watercolor Wildflowers Monthly Newsletter here featuring a rainbow Icosahedron.  What’s that?  Read on.

Resinart nightlights and lighthouses on display in a darkened room. Colors range from red to yellow to aqua to green and blue.
Glowing nightlights and lighthouses on display in a darkened room. Colors range from red to yellow to aqua to green and blue.

This month’s winner of a Planetary Nightlight is Robert at RobertLovesPi.net, a very cool blog about polyhedra and tessellations. Subscribe to my newsletter for a chance to win!   

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Customer Newsletter      July 2025

Rainbow Icosahedron in Resin

Exploring the intersection of art and science, the Icosahedron embodies principles of symmetry and balance. Its structure has fascinated mathematicians and artists alike, inspiring countless creative projects. At my studio I’ve kept going with the Icosahedra idea (plural of Icosahedron). Its like a geodesic dome but all the way ’round. The trick is finding best way to assemble these beveled equilateral triangles.  Mathematically, it will fit. The best outcome requires  precisely made 60° resin triangle chips of equal thickness. Beveled edges of 15° are sanded on my vertical belt sander.

Alcohol Pigment

I’ve found alcohol pigment is a good way to color the hard resin after the sanding and clean-up. Primary and secondary 3″ colored triangles are distributed evenly.  Each Icosahedron has 20 triangles. So I make 3 red, 3 blue, 3 yellow, 3 violet, 3 orange, 3 green (rainbow) and then 2 clear triangles.  The coloring may be simple but its the best way to avoid muddy (tertiary) color accidents.

Alcohol pigment effectively colors the cured resin post-sanding and cleanup. Each Icosahedron comprises 20 evenly distributed colored triangles. The distribution includes 3 red, 3 blue, 3 yellow, 3 violet, 3 orange, 3 green (rainbow), and 2 clear triangles. This simple coloring method helps me prevent undesirable muddy colors. Muddy colors are the mixing of less bright, less clear, tertiary colors by accident. I want these Rainbow Icosahedron to be mesmerizing and fun to look at.

colorful display of Icosahedron equilateral triangles in rainbow colors laid out on a white board
Equilateral triangles to be used to make a three-dimensional Icosahedron

How to Assemble an Icosahedron in 20 Pieces

I found the best way to assemble the Icosahedron from studying the unfolding diagram. Unfolding diagrams show what elements make up a three-dimensional object (flattened pieces). Turns out you start with the middle.

colorful pentagon with triangular elements in primary and secondary colors forming a star and another pentagon
This is the inside of two-thirds of an Icosahedron. The bottom triangle edges of the crown are visible first, then the inside of the alternating crown triangles, then the pentagon top.

The middle band of 10 triangles up then down should be taped edge-to-edge on a smooth flat surface with 1/2″ masking tape. Carefully raise the chain of triangles onto its side and curl it into a circle. Tape that last triangle to the start of the circle. I carefully add more masking tape, tightening and holding the triangles more firmly together. This makes a crown where curiously one triangle tips inward 5° and the next triangle tips outward by about 5°.

I form the top pentagon as five triangles pointing into the middle and pulled up at the center. Starting these shapes with masking tape saves a lot of frustration. Add the top to the crown. Match, fit and tape edges tightly together in all directions.

The bottom pentagon goes on the same. If made with near-exact equilateral triangles, then a tight fit can be achieved. The taped pieces are glued together carefully with tiny resin welds between tape. 

Two heavily colored Icosahedra resting on a white plastic board in the sunshine. The image cast from light through the Icosahedra appears on the white plastic board.
Two heavily colored Icosahedra resting on a white plastic board in the sunshine. The image cast from light through the Rainbow Icosahedra appears on the white plastic board.
Colorful pentagon shaped Icosahedron sitting on a sunny window sill. The equilateral triangles are colored in a washy technique and they are colored red, blue, yellow, purple, green, or orange.
Colorful pentagon shaped Rainbow Icosahedron sitting on a sunny window sill. The equilateral triangles are colored in a washy technique and they are colored red, blue, yellow, purple, green, or orange.
Four Icosahedra and a Pentagon Bowl sitting on a white plastic board. One Icosahedron is totally clear. Two Icosahedron are heavily colored with transparent primary or secondary colors. The last Icosahedron is thinly colored with a washy effect. A clear pentagon bowl sits adjacent.
Four Icosahedra and a Pentagon Bowl sitting on a white plastic board. One Icosahedron is totally clear. Two Icosahedron are heavily colored with transparent primary or secondary colors. The last Icosahedron is thinly colored with a washy effect. A clear pentagon bowl sits adjacent.

Finishing the Rainbow Icosahedron

All of these get a clear resin finish.  I’m trying different pigments and transparency ideas.  And I’ve got some one-way mirror film that will create an infinity effect.  You’ll see forever next month as well as some food-safe stylish Pentagon Bowls!

CALL OR VISIT MY STUDIO 5069 Leavenworth Street Omaha, NE 68106 (402) 943-7516

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June Newsletter: Icosahedron

Very clear icosahedron resting on window sill capturing the light in the texture of resin and equilateral triangles

Happy June!  Watercolor Wildflowers Monthly Newsletter featuring brand new geometric art. The Icosahedron.

Resinart nightlights and lighthouses on display in a darkened room. Colors range from red to yellow to aqua to green and blue.
Glowing nightlights and lighthouses on display in a darkened room. Colors range from red to yellow to aqua to green and blue.

This month’s winner of a Planetary Nightlight is Nita Upchurch of redefinedhome.com in Des Moines, IA. Subscribe to this newsletter for a chance to win!   ENTER Drawing by ->  SUBSCRIBE

Customer Newsletter      June 2025

Icosahedron Art in Clear Resin

I see new resin art ideas wherever I look! From nature to man-made structures, there are fascinating ideas in art just waiting to try.  This month it’s the Icosahedron.  A clear or colored, three-dimensional tetrahedron, formed with 20 equilateral triangles. It has a penta-gonal pyramid on “top”, and same on the “bottom”. with a band of five up and five down alternating triangles holding the top to the bottom.  As you turn it over in your hands, it’s hard to tell where the top is.  Each side is the same! Roll it over and there’s another pentagon. You could also call it a geodesic sphere or a polyhedron.

Red Icosahedron play structure. Copyright free Pixabay. December 26, 2016
Red Icosahedron play structure. Copyright free Pixabay. December 26, 2016

My first attempt was with cardboard.  I wanted to get the assembly correct and its hard to tell where to start.  Can a flat paper be cut and folded into a 20 sided geodesic ball? The answer is yes but a stiffer material is needed. 

I cut 3″ triangles from a sheet of 1/8″ plastic acrylic. How to fit, how to join these triangles together? What angle should they be to each other.  The angle between each side should be 138°.  This is called the dihedral angle. It is figured with college level math that I don’t remember any longer. Making 3″ clear or colored resin triangles in exact 60° angles and consistent dimensions is the next challenge. Precision is key to a good fit.  I bought some laser-cut acrylic triangles in the end to keep everything tight and attractive. I used these to create a mold so I can cast the triangle in any color using liquid two-part epoxy resin.

There’s the awkward fit with square edges so the mold includes 21° +/- angle on the inside faces. Each chip touches three times with a 138° interior angle. An interlocking design would help. The result is what you see here:

Icosahedron resting on table in front of a yellow wildflower lighthouse. The icosahedron is made from clear epoxy resin and has 20 equilateral triangles fit together in pentagon shapes repeating around the geodesic figure.
Icosahedron resting on table in front of a yellow wildflower lighthouse. The icosahedron is made from clear epoxy resin and has 20 equilateral triangles fit together in pentagon shapes repeating around the geodesic figure.

These unique pieces of art make a perfect gift for Father’s Day – for the man who has everything – except an Icosahedron.

Basic models are only $45.  If you want an LED light then add $15. Made-to-order or buy online from watercolorwildflowers.com/store/

CALL OR VISIT MY STUDIO 5069 Leavenworth Street Omaha, NE 68106 (402) 943-7516