I found this an interesting and challenging exercise.  I will definitely repeat this with other foci. I combined my interest in neurographic art and my interest in learning coloured pencil techniques.

The picture below shows most of the pattern with the first layer of pencil and one area with the second layer (the darker green area).  I used prisma colour, polychromos, and Derwent light-fast pencils and blending medium.

The next picture is the completed mandala with fiend lines and fixations. 

The colours are a bit off in the process of photographing and uploading, but they give the general idea. 

I was pleased with how it turned out and I will definitely repeat this with other foci.