Try to work with the helping elements before looking at the solution…

Helping elements

• we work in TraModel

• make a new method regenerationAroundMothers(TraScene newScene) and call it instead of regeneration()

• loop on the trees, like in processEvolution () for the growth

• consider only tree with getAge () > 20

• calculate double maxDistance = mother.getHeight () / 2d;

• you can get the mother's coordinates with something like this: x0 = mother.getX ()

• for each new tree, distance to mother can be calculated like this: distance = random.nextDouble () * maxDistance;

• find an alpha angle (radians) around the mother: alpha = random.nextDouble () * 2 * Math.PI;

• calculate x and y according to distance and alpha: x = x0 + Math.cos (alpha) * distance; (same for y with sin())

• create the tree (like in the original regeneration () method) and add it in the scene

A possible solution