How to make Edge Lit Flouro Channel Letters?

[Jose Ortiz]

Hello Fellow Sign Makers!
I am trying to understand how these type of channel letters are made. Anyone mind advising me on how these type of letters are constructed ? They look a little more complex then regular channel letters. To me they look like acrylic formed letters with reverse channel letters inset within the acrylic formed letters.
What do you guys think?

 

[Bradley D]

Maybe vinyl applied to acrylic on inside as well. Not sure. Cant really tell much from photo.