Launch Adobe Illustrator on your computer and create a new Illustrator document. Choose 1000px as height and width of the canvass and draw a rectangle (1000px × 1000px) using the Rectangle Tool. Align the rectangle Horizontal and Vertical Centre from the Alignment Panel.
Using the Pen Tool, draw three lines in the desired shape and colour
Choose the Blend Tool and click each of the three lines you drew earlier one after the other. When you have clicked on all three lines, you will see 5 lines in total. Double click the Blend Tool icon in Illustrator and change the spacing between lines if required using the ‘Specified Steps’ option from the ‘Blend Options’ dialogue box.
Use the Convert Anchor Point Tool to smooth out the line connecting individual patterns in the blended group to each other. Simply click the middle anchor of the line and drag it until desired shape of the curve has been defined. If you want to make changes to the shape of the three lines you initially made, click the blended group and make the desired changes.
You might want to change the Transparency of the blended group. This can be accomplished changing the Opacity of one or more lines to 0%. This will make the group look as if it was blended into the background.
To fix the blending if it appears in the opposite direction, select the Pen Tool and change the direction of the blended group by clicking on one of the ends of the curve.