Creating an abstract background effect

Create an ellipse using elliptical shape tool.

Enable "subtract from shape area" at the top bar. Create a circle using elliptical shape tool.

Similarly create more circles.

Press Ctrl+T. Right Click and select Warp. Adjust the nodes as shown.

Select all the paths using path selection tool. Duplicate the path. Press Ctrl+T again. Move the anchor point as shown and rotate it 45°.