# How can I create a double helix?

I want to create intersected curved line like this

, I use `Pen Tool` but can not get the same as this , and searched a lot for already built through google , but all I got were curve lines not like this, any tutorial or any idea?

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There are a lot of ways of doing it but the first tool or idea that came into my mind is using the pen tool.

![First, you have to grab your pen tool and draw the one shape like this (apparently I suck with the pen tool as well so you might wanna tweak yours a bit more).Create a new layer then fill this with any color. Then add your gradient to it. Select your layer then duplicate, grab your marquee tool then right click>flip horizontal. Lastly, merge your duplicate and your first layer, and tweak it till you get your desired curves. You might wanna duplicate this again to make a DNA effect (duplicate>flip vertical). I hope this helps!1

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Thanks a lot . that was helpful. I'll try to repeat it – rabar kareem Dec 29 '13 at 20:30

A know this is an old post but I feel like I should say something. Please have a look at something I created on http://isabel.rosety.com. The I use generates SVG from PHP code, so you can dynamically compute and generate different results according with the paremeters you prepare in your code.

There is another post related to DNA double helix on this stackexchange post. Here's the main takeaway:

I have been "playing" with this kind of helix lately. I use a PHP library that I developed to generate SVG and the image I generate is SVG. If you talk about straight double helix, the solution is not difficult since it can be generated with my scripts and the helix is based on the mathematical expression:

``````  x = r * cos(t);
y = r * sin(t);
z = k * t;
``````

The final helix I was working with is more difficult because it is what corresponds to plasmid circular double helix.

I will add the base pairs that are still missing. Once you get the image in SVG you can save it and open directly it in Inkscape

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I edited your answer to include what you put in the other question. If you think it needs more refinement for this question please use the edit button to do so. – Ryan Oct 25 '15 at 23:33