Make a new document. Click on[ Custom Shape Tool (U) ].

Choose shape below

Change its color to #21a14a and Rasrerize its layer.

Press Ctrl + T and right click on it, then click Rotate

Go to Select > Modify > Contract … set amount of it to 2 pixel.

Result :

Now make a new layer and fill it by #61d62f.

Now hold down Alt key for subtraction.

Now make a new layer and click  Gradient Tool (G) .
Click on selected gradient to edit it.

Now drag as shown.

Your result should be like this:

Now pick a smooth brush and apply following settings:

Your result should be like this

Now make a copy of it and rotate it (180%)