Questions about NightShade document

[xiaolese1]

I read the "Nightshade: Near Protocol Sharding Design 2.0" paper. A beautiful design and inspire me a lot.

But I think the section 3.4 is quite confusing.

At the end of section 3.3, chunk producer is introduced. In 3.4, the parts are sent to the validators via onepart messages, but block producer also have onepart messages? besides, the onepart message send to block producer and validator, no same shard other chunk producer?

looks like section 3.4 is not update like 3.3 or next section make me confused.