TWIST
Product Design
Consumer Audio
Consumer Audio
A lighthearted ritual before I start writing.
This is a twist-action ballpoint pen entirely encased in flexible silicone rubber. When you twist the barrel to extend the tip, the silicone flexes smoothly in response to the motion, causing the pen’s shape itself to change.
Could we transform the single action required for writing—not just into a mechanical process, but into an experience that leaves a lasting impression on the hand? Creating a moment of gentle surprise in the motion leading up to the first stroke was the starting point for this design.
A Harmony of Materials and Functionality.
In a typical ballpoint pen, components are arranged according to their specific functions—such as the click button for extending the tip and the grip for holding the pen—and the overall design is shaped by the relationships between these parts.
With TWIST, rather than assigning these roles to specific parts, we aimed to eliminate the boundaries between materials, functions, and design as much as possible. The soft silicone casing serves as the grip while also responding to twisting motions, reflecting those changes in its shape.
Rather than designing each element separately, we envisioned a pen in which the functions necessary for writing are seamlessly integrated into a single, continuous body.
When the main unit is twisted, the silicone body stretches, changing its dimensions and generating strong elastic force. To ensure a stable relationship between the outer casing and the internal mechanism, it was necessary to make precise adjustments to the materials, shape, and structure, and development took approximately two years. Through KACO’s engineering and ongoing testing, this simple design has been successfully brought to market.
Analysis Based on Prototyping
We repeatedly created mockups with different shapes to verify the amount of twisting required, the twist in the exterior profile, the thickness, and the feel when held.
If we emphasized the operation too strongly in the design, it would become an awkward everyday writing instrument; if we toned it down too much, TWIST would lose its unique character. By actually holding it, twisting it, and writing with it—repeating this sequence of actions—we sought to strike a balance between intuitive operation and the natural feel of a writing instrument.
Twist the box, too
As TWIST neared completion, I wanted the packaging to reflect the TWIST spirit as well. Although the idea for a package with the top and bottom of the tube twisted by about 30° came to me quickly, I had to repeatedly cut out the flat pattern by hand and assemble it to verify the shape before arriving at the final version.
