FLAT CONTENT

repeated pattern of a surface being
- flat surface
  - layers
Enclosed space
- Respectively; in Bodies whose superficies is composed ‖ either all of straight lines: or of lines bending in the midst, outward: or inward.
  - PLAIN, level, flat, even.

3D FLAT DOMAINS

cylinder, aulos, auletes,fistula ,sinus, shunt ,trachea,pipe,oesophagus, vessel, aqueduct,duct,canaliculi, canal, passage, tract,road,meatus,gullet , cylinder,voyage, via,anastomosis
rod, bar ,
infundibulum,
Isthmus, neck , connector