I found a picture of a rainbow online to use for my project. When I use the Trace Image feature, it makes a vector that has double lines, which is not what I want.

I decided to test out the new Edit Nodes feature in XCS 2.0, to see what it's capable of. I will manually trace the rainbow image, so that there is only a single line.

1. Open the rainbow image in XCS.
2. Click on the Vector Pen tool on the left hand side. 
3. Starting at the base of the rainbow, I click to add my first vector node. I try to click in the middle of the rainbow next, and finally the base of the rainbow. This makes a triangle (Picture 1).
4. Exit the Vector editor by clicking ESC on your keyboard or right-click on your mouse.
5. Click on the triangle and click on Edit Node on the right side. 
6. Click on the top center node, and click on Perfect symmetry as the Node type on the left-hand side. This will make an arch.
7. Square bars will appear. Pull and drag the squares to match the rainbow shape as close as possible. Click Done. 
8. Continue repeating steps 2 - 7 to manually trace all the rainbow arches and clouds.

Tip: Add more nodes to the rainbow arch as necessary to help match the picture better. Do this by clicking anywhere on the arch line in Edit Node mode. The more nodes there are, the more control you have to how the line is bending/arching. (Picture 2)