Origin of Cocoon Nebula.

Cocoon Nebula at end of filaments. Image credits: ESA/Herschel/SPIRE/PACS/D. Arzoumanian (CEA Saclay)

Star studded filaments join to Cocoon Nebula as a connection in evolution. This maybe part of matter transit through these filaments as conduits (though no known process can achieve this) is proved by the formation of stars along their length as a connection to massive matter transfer. The very centre of the Cocoon Nebula sits on top of a column of filaments as the termination point and suggests an entity or end point resides there. From that centre (probably something like a White Dwarf) matter expands almost symmetrically to form the Nebula as a growth system of that transfer. There is no question that a connection exists between those double filaments and the Nebula with associations, via unknown evolutionary processes, to accumulations of matter as new stars.
Other filaments and connection to 'ribbons' of stars may have termination points as types of nebula, and there is evidence of this, that poses the questions: How can matter pass inside filaments and what process of transfer? Where a whole other explanation may exist for their formation.

Eta Carinae. Symmetrical expansion of matter that forms nebula with two tube like structures, connected to central object, as termination point for transfer through double filaments.