Sitting cross-legged often causes spinal problems, such as scoliosis. FRICTION detects your bad sitting posture and reminds you to correct it. When the wearer sits cross-legged, the rough back material of the jeans rubs against the soft front one, causing fading. This shows on corresponding areas based on different cross-legged sitting postures. Once fading appears, specific posture icons are revealed to remind the user to correct their posture. Even after fading, it is still a trendy item with a tattoo-like pattern.