People naturally like things with a sense of flow, and this state is called “mental flow” in sports psychology. This is why things with beautiful curves are always pleasing to the eye. Designs that give a sense of “flow” in industrial products address the dual needs of physical application and design aesthetics. In the field of visual design, we also need visually more beautiful and smooth curves to make our designs a more pleasing aesthetic experience. The clean and edgy curves of the classics make these products timeless and purely aesthetic. These design legacies have influenced countless modern designs, and I designed the variable font KOIE Master™ inspired by those classic product designs. KOIE Master™ is a sans serif variable font with a geometric sense of equilinear letter structure and rationalistic aesthetics. It relies on the Glyphs platform to create and define different variant axes, such as weight and width axes, allowing the font style to change from very light to very heavy, and from narrow to wide; And a custom ink-trap axis has been innovatively added, which designs for certain characters combining functionality with decorative features. This font is now available with 475 characters and 1202 glyphs, 3 axis and 121 instances, and 45 OpenType features. KOIE Master™ variable font family covers uppercase, lowercase, small caps, lining figures, old-style figures, tabular figures, tabular old-style figures, fractions, small figures, small-cap figures , currency symbols, math symbols, geometry symbols, and a range of punctuation. The variable font family that support Latin scripts systems including Western and Central European and even Hanyu Pinyin and Esperanto. This variable font can be used for body copy typography, but also has rich expressiveness in short text or headline typography, with powerful usability and wide adaptability. This font is still under development.