Create solid between element

I would like to create a solid between it’s 4 element via dynamo. I do not master Dynamo on the creation of geometry, unfortunately for me.
It’s been some day that I’m looking for no optimum result.
Do you have a solution ?
I search with the surface or solid tool by subtraction and surface intersection without result

Can you make a quick sketch of the four geometries currently, and then outline what your desired result is?