Describir: Part4: Architecture of Form, variations un tube structure

  ______   __   __    _  _      ___      _____      ___      ______   _    _   
 /_   _//  \ \\/ //  | \| ||   / _ \\   |__  //    / _ \\   /_   _// | || | || 
 `-| |,-    \ ` //   |  ' ||  / //\ \\    / //    | / \ ||  `-| |,-  | || | || 
   | ||      | ||    | .  || |  ___  ||  / //__   | \_/ ||    | ||   | \\_/ || 
   |_||      |_||    |_|\_|| |_||  |_|| /_____||   \___//     |_||    \____//  
   `-`'      `-`'    `-` -`  `-`   `-`  `-----`    `---`      `-`'     `---`