Self-Rotating Koi Fish Sphere

In this Instructable, you will learn how to make a rolling sphere that allows the koi fish sphere in the center to always point down.

I wanted to make an object that could stay relatively stable while the surrounding structure is moving around. In this case, a pair of Koi Fish in a pond represent Yin and Yang, with the solid resin appearing to move like water. The outside rings represent the cycle of seasons, and under starry nights.

To do this, we start with a "core", the blue part shown. This will be the center of universe where Koi Fish sits. It is the origin of a 3-D coordinate space. Then a model of three concentric circles (green, orange and blue) with increasing diameters form spheres that allow you to still view the koi. The key for free rotation is the connection between these circles: hinges between each of the layers allow the whole sphere to rotate around the x, y, and z axes. The rings need to be strong but flexible enough to support rotations.

So, the inner sphere is a plastic ball with diameters slightly less than 4" (10cm). The three circles are bamboo hoops of diameters 6", 8", and 10". The connection for the circles (short green line segment) should each be exactly 1" long. This is because the difference of the outermost blue circle (10") and next orange circle (8") is 2", and you need 2 connection to fix them together, so each connection must be 1". So for the connection between hoops, we will use 360° rotatable, small windsock clips with a dual swivel hook.

• Polymer clay (white, red, and black or your choice of color sets for the Koi fish, green/yellow/gold for lily pad), polymer clay glaze (optional) and clay shaping tools.
• One 100mm Clear Plastic Fillable Ornament Ball (with two semi-spheres connected to loops for hanging on one side)
• Epoxy resin & paint
• Bamboo flower hoops (x3 of 6”, x3 of 8”, x3 of 10”)
• Acrylic paint for crafts
• Paint brushes
• 6 Windsock Clips - 3" Dual Swivel Hook & 360° Rotatable
• Dollar store gem stickers

Shape a polymer clay into the body of the fish as shown.

Roll a small flat sheet of red polymer clay, scratch small pieces off and gently stick and flatten it onto the koi fish body.

The handle of the clay tool I use has a diamond pattern. I rolled it over the fish to create a texture like scales and finalize the shape of Koi fish at the same time. You can use any pattern you want.

Roll a thin sheet of white polymer clay, carefully carve the stripes on tail fin, and connect it to the fish body.

Roll more small pieces of white polymer clay, carve the stripes on these fins, and attach them to the fish body. I made two side fins at upper body and two more side fins near the tail.

Repeat to make another fish, preferably of a different color.

Glaze and bake at 270C for 15-20 minutes.

Use a mixture of green, yellow, tan, and gold polymer clay to make several lily pads. Glaze as needed and bake.

Use epoxy resin to make "water" by adding some aquamarine paint to the epoxy mix.

Take half the ornament ball. First fill it with the resin to around ½ from the bottom, so the two fish can fit in the ball once the first layer cures. Then, position both fish on the cured first layer and pour the resin mix to cover the fish. You can optionally use some fishing line to position the fish (in our case, it was not necessary)

Use clear epoxy mix to make some drops that we can later use as dew drops on lily pads.

We use 9 hoops, or 3 of each size: 6”, 8” and 10”.

For each hoop, drill 4 evenly spaced holes. The best way to do this is measure the total length of the hoop (or calculate the circumference then divide by 4).

Design (You may use your own, but here's what we did):

For the smallest 6” hoops, we would like to simulate the color of a lake, so color it with green, blue, and white.

For the middle 8” hoops, we would like to show one season with each half circle: green for spring, yellow gold for summer, orange gold for fall, and blue for winter.

For the biggest 10” hoops, we would like it to symbolize the stars. Again, each half circle represents one season. The blue colored background was decorated with constellations for each season - Bootes in Spring, Corona Borealis in Summer, Cassiopeia in Fall, and Orion in Winter. To make it easier, glue the constellation at the last step though.

Now to assemble.

First, the ball. The ornament ball can be connected with the hanging pieces that came with it on one side, however, we still need to drill holes at the other side so that we can attach it to the rings.

Next, put two 6” hoops together over the ball and crossed perpendicularly as shown. Align the intersection of the rings with the connection points of the ornament (A to B, C to D). Use wire (green arrow) and a dual swivel hoop (black arrow, we bought windsock clips but removed the extra hooks) to connect the ball to the intersection of two hoops, for each connection point of the ornament. We decorated it with some buttons (orange arrow) or beads (optional). Add the third 6” hoop so that it crosses both existing hoops in the middle. Connect the new hoop to the existing ones where they intersect so they form a sphere together.

Then, add a swivel hoop on 2 opposite connections (G & H). connect those swivel hoops to two 8” hoops, much like with the first sphere (G to J, H to K). Add the third 8” hoop to the middle of the existing 8” hoop-ball in the middle, then add 2 swivel hoops on opposite intersections.

Finally, add the last 10" hoop and connect in the same way.

Please see the pictures. Essentially, we are creating connections along the x (ornament -> first), y (first -> second), and z (second -> third) axes, centered at the fish ball for every concentric sphere.

This, together with the swivel hoops, allow the outer hoops to move freely while the center stays stable. The gravity will make the central sphere stay upright.

Hot glue on the lily pads, dew drops, and constellations from the four seasons.

I hope you enjoy this project as much as I do. I like how it integrates math, art, and engineering! With a touch of ZEN, in time, space, and universe :)