#!C#
  private void RunScript(System.Object cloudObj, ref object cloudOut)
  {
    // Since Rhino.Geometry.PointCloud is already in the SDK, we don't need any dependencies
    // And our object can be cast directly
    PointCloud cloud = (PointCloud) cloudObj;

    Random rng = new Random(2);
    // Iterate through the Rhino.Geometry.PointCloudItem list
    foreach (PointCloudItem item in cloud) {
      // Do something with it
      item.Color = System.Drawing.Color.FromArgb(rng.Next(0, 255), rng.Next(0, 255), rng.Next(0, 255));
    }

    // Since a point cloud is IEnumerable of PointCloudItem, we need to wrap it as an object
    cloudOut = new GH_ObjectWrapper(cloud);
    // We will then be able to plug it into the point cloud parameter to have a GH_PointCloud
  }

#!python

from Rhino.Geometry import PointCloud, PointCloudItem
from System.Drawing import Color
from Grasshopper.Kernel.Types import GH_ObjectWrapper
import random as rd

rd.seed(2)
# cloud is the component input, a GH_PointCloud or Rhino.Geometry.PointCloud
for item in cloud:
    item.Color = Color.FromArgb(rd.randint(0, 255), rd.randint(0, 255), rd.randint(0, 255));
cloudOut = GH_ObjectWrapper(cloud);