Grade 3-4: 1 vertical bar, 2 horizontal bars.

Grade 5-6: 1 vertical bar, 3 horizontal bars.

There is no difference between grade three steel and grade two steel on the surface, but the materials are different, so the physical properties are different. But both surfaces are rebar. Both sizes are available.

Abstract:

Cassirer understood symbols as a form from special abstraction to universality. "People have developed an ability to distinguish relationships." This ability to separate relationships is called "reflection" by the German philosopher Herder. That is, people can extract some fixed components from the floating perceptual flow in order to separate them for study.

This abstract ability is not available in animals. This shows that the concept of relationship depends on the concept of symbols. Without a rather complicated symbol system, the concept of "relationship" is impossible. Therefore, "if there is no symbol system, people's life will be limited to their own biological needs and practical interests, and they will not find the way to the ideal world."