TRIZ Principle No. 14

Instead of using rectilinear parts, surfaces, or forms, use curvilinear ones; move from flat surfaces to spherical ones; from parts shaped as a cube (parallelepiped) to ball-shaped structures.
  • Use arches and domes for strength in architecture.

Use rollers, balls, spirals, domes.
  • Spiral gear (Nautilus) produces continuous resistance for weight lifting.
  • Ball point and roller point pens for smooth ink distribution

Go from linear to rotary motion, use centrifugal forces.
  • Produce linear motion of the cursor on the computer screen using a mouse or a trackball.
  • Replace wringing clothes to remove water with spinning clothes in a washing machine.
  • Use spherical casters instead of cylindrical wheels to move furniture.