Power lines

• 

  
  Power lines
  1969
  
• 

  
  Aswan Hi..er lines
  1968
  
• 

  
  cogwheel..er lines
  (4 stamps, 1958-1959)
  
• 

  
  Power li..ountains
  1972
  
• 

  
  transfor..er lines
  1962