Volvo graphic logo is formed by the double-ring shape of the wheel, and point to the top right of the arrow.
沃尔沃图形车标是由双圆环组成车轮的形状，并有指向右上方的箭头。
2
The size and number of steel wheel lug's holes, formed within the same distance, reflect directly its motion resistance when rolling in paddy field.
水田铁轮在水田中滚动时，在相同区段上所形成的刺孔的大小与多少直接影响共滚动阻力的大小。
3
Its principle is adding the metal powder into the resin binder as addition, then electrolyzing after addressing the wheel, so that the metal content can be dissolved and the pinholes are formed.