For this step, we need to ensure that we have good outlines for the shapes that we will be building. It works well to fill in the areas we want to keep with different colors.. making a sort of "cartoony" version of the image.  The other thing here is that you want all of the lines connected.. no gaps around the outline.  It's okay to leave the thin black line between shapes, but it's not necessary.

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Step 3: convert to DXF