TreeSet animation using reftree (https://github.com/stanch/reftree)

TreeSetAnimation.scala

import reftree.{Diagram, Utils}
import scala.collection.immutable.TreeSet

val adding = Utils.iterate(TreeSet(1), 15)(s ⇒ s + (s.size + 1))
val removing = Utils.iterate(adding.last, 15)(s ⇒ s - s.size)

Diagram().renderAnimation("treeset", tweakOptions = _.copy(
  delay = 200, onionSkin = 0, diffAccent = true,
  verticalSpacing = 1.1, highlightColor = "coral1", density = 75
))(adding ++ removing)