Cascading Paper Dragon Ring Decoration

In the spirit of Pi Day, I wanted to make some craft related to circles and angles. After all, pi is intimately connected with radian angles and circle properties - so what better craft project could there be than something that demonstrates the beauty of rotations?

A waterfall card is an interactive paper craft in which a series of panels flip sequentially, creating a cascading “waterfall” effect. A circular waterfall card is a variation where the panels are arranged along an arc to resemble a circle.

Typically, a circular waterfall card is constructed by attaching multiple panels to a folded, arc-shaped pull strip (forming most of a ring, with a deliberate gap). One end of the strip is fixed to the card base, while a handle at the other end drives the motion; when pulled or rotated, the panels flip forward one by one. Each panel overlaps with the previous one to form a hinge, which enables the flipping action. Because of this overlap requirement, a full circle is not possible—without a gap, the first and last panels would collide and prevent movement. For example, a 20-panel design with each panel spanning 15° covers only part of the circle, leaving a gap of 60°.

I wanted to make a complete circle of waterfall cards. This requires some design & implementation improvements, specifically: First, the pulling mechanism can be moved from the center to the outside edge of a rotating ring, allowing bidirectional (clockwise and counterclockwise) motion and enabling the handle itself to rotate. Second, the hinging mechanism is implemented in a new way to provide sufficient strength for a fully circle movement. Third, the handle is attached to the second-to-last panel. This helps create a full-circle effect while also reducing the force required for the full-circle push/pull motion.

Material:

1. Bristol Paper or any heavy card stock
2. Foam board
3. 5mm wooden stick
4. Glue
5. Header bracket with 3x2cm base (if you do not have this, you can make one with cardboard)
6. Nuts and bolts

Tools:

1. Compass and Protractor
2. Ruler
3. Scissors

Optional (for decoration only)

1. Watercolor paint
2. Markers
3. Decorative paper

Instead of using panels that span 15°, we use 20° panels to simplify the construction. We start by creating a 90° ring segment with an outer radius of 14 cm and an inner radius of 5 cm. Each panel is folded along a 35° line so that, after folding, the visible (non-overlapping) portion of each panel spans 20°.

Make a total of 18 such panels.

Note: It turns out that we only need to use 17 panels because either the first one or the last one can close the gap when displayed.

Attach the larger section of the second panel to the smaller section of the first panel, aligning the arcs carefully as shown.

Repeat this process for all panels.

Now the fun part - decoration! I chose this pattern:

https://www.britishmuseum.org/collection/object/A_1885-1227-92

Credit for the template goes to zhaojialong17@littlerednote.

It involves a lot of repetitive work due to the overlapping panels, but I’m pleased with how it turned out.

Cut out the following pieces:

1. Waterfall board: radius 14 cm
2. Rotating ring (middle): outer radius 16.5 cm, inner radius 3 cm
3. Connecting discs: 4–5 circles, each with radius 2.5 cm
4. Base frame pad: 16 × 16 inches (to fit the frame)

Decorate the components as desired.

First, fold and attach the second panel (the “head” end) to the waterfall board as shown. The second panel is used so the first panel can help fill part of the gap if needed.

Next, insert the stick through the bracket formed by the second-to-last panel, as shown, and secure it with glue or staples.

Then, install the head bracket on the outer edge of the rotating ring.

Important:

1. Position the assembly onto the rotating ring and test before fixing the bracket in place.
2. Adjust the bracket height as needed to ensure smooth panel movement during rotation; add extra cardboard layers if additional height is required.

Finally, secure the connecting discs into a solid stack. Attach the stack securely to the center of the top board, pass it through the rotating ring, and glue the other end to the base frame.

Add any additional decorations as desired. I created a corner decorative stencil using the attached template.

The keys to this project are:

[1] Accuracy — supported by solid mathematical design and implementation (thanks to π!).

[2] Adjustment — careful fine-tuning is needed to ensure smooth motion, but the result is well worth the effort.