local drawBackground = function()

  background = display.newImage( "background.png" )
  background.x = 240; background.y = 160

  gameGroup:insert( background )

  ground = display.newImage( "ground.png" )
  ground.x = 240; ground.y = 300

  local groundShape = { -240,-18, 240,-18, 240,18, -240,18 }
  physics.addBody( ground, "static", { density=1.0, bounce=0, friction=0.5, shape=groundShape } )

  gameGroup:insert( ground )

end