3D tubes - part 1

Create a new document. I used a 1000 x 600 pixels.

Pick a good looking gradient. In my example I used a blue color, but the choice of color can be up to you. This step is totally optional but next I filled my layer with 50% gray, added "Halftone Pattern" which can be found in Filter > Sketch > Halftone Pattern. Last, I changed my blending mode to "Soft Light". I just felt like it would look better if what I am about to show you is on some type of a background.

Next, select an Elliptical Marquee Tool and create a circle while holding the Shift button. Put the circle on the left top corner of your document. Then, fill it a "Copper" gradient, and desaturate it.

Now, select a pen tool, and draw a path that looks similar to mine. Make sure that you start the path of from the center of the circle.

Now, select your smudge tool. Put the hardness and strength to 100%. Now make the size a little bit smaller than the circle that you made and click once inside of it with smudge tool.