Поступательное движение

Missing, extremely new, or very obvious to obtain.

Reference to lyrics of the song "My Skateboard Shoes" by Hua Chenyu: "Rub, rub, I'm rubbing on this smooth floor." Because Bubble Bridge is made to look like the vert ramp used in vert skateboarding, traveling it again and again is similar to the skateboader jumping the ramp repeatedly. - Credit: Necrosyrtes