OpenGL was made for screensavers. Has anyone here created a DirectX screensaver?

OpenGL wasn't made for screensavers (it was made as a general purpose rendering API); maybe you're getting confused by the old Windows OpenGL screensavers here?

And yes, I've made D3D screensavers. It's simple; you make them exactly the same way as an OpenGL screensaver aside from the API differences. Why would they be any different? MS even ported their old OpenGL screensavers to D3D over a decade ago; this is something that's existed for a long time.

thank you .

OpenGL was made for screensavers. Has anyone here created a DirectX screensaver?

Yes. Screensavers is all you can do with OpenGL and DriectX (or if you want the fastest screensavers in AMD hardware, use Mantle), you can even play with some of those (also called "interactive screensavers" or videogames).

Actually, OpenGL was made for CAD.

The old DirectX 9 SDK had a good example of how to build a screen saver using Direct3D. It's not difficult at all.

It's not even really about OpenGL or DirectX. You can make a screensaver with GDI or with pixeltoaster if you want to, the only difference between a screensaver and your average fullscreen program (at least on Windows, but I imagine it's the same on most operating systems) is that screensavers follow some conventions, listen to some specific events, and get registered with the operating system as a screensaver, if applicable, so that the user can select it in the OS's control panel and the OS can launch it as needed. Also Windows screensavers get a cute .scr extension.

Beyond that it's just like any other program and you don't have to use anything in particular, as long as it does the above (and, optionally, actually draws something) it's a screensaver. Nothing to do with whatever graphics API you use.