@startuml
title Step 4 — Second Iteration After Reversing Node 2

object "Node 1" as n1 {
  value = 1
}

object "Node 2" as n2 {
  value = 2
}

object "Node 3" as n3 {
  value = 3
}

n2 --> n1 : next
n1 --> "null" : next
n3 --> "null" : next

object "previous" as prev
object "current" as cur
object "next" as nxt

prev --> n2
cur --> n3
nxt --> n3

note bottom
After processing Node 2:

2 -> 1 -> null

The reversed part grows from the front.
The remaining part starts at current.
end note

@enduml