What is where is the 4th ninja turtle on roku screensaver?

As an AI language model, I don't have access to Roku screensavers and I'm unaware of the whereabouts of the 4th ninja turtle on Roku screensavers. However, it's possible that the 4th ninja turtle may be featured in some screensavers or animated backgrounds related to the Teenage Mutant Ninja Turtles franchise on Roku devices. You can explore the Roku channel store or search for Teenage Mutant Ninja Turtles-themed screensavers to check if the 4th ninja turtle is included in any of them.