Spiral staircase with patterned railings in gray and black tonesSpiral staircase with patterned railings in gray and black tones
The contrast of smooth curves and clear edges, a girl and a motorcycleThe contrast of smooth curves and clear edges, a girl and a motorcycle
Curved glowing colored lines on a black backgroundCurved glowing colored lines on a black background
В математике: всякая непрямая линия. Кривая линия, изображающая рост или падение чего-н. в развитии какого-н. процесса.