function onTick(timePassed)
  --levelgen:addItem(Turret.new())

  items = {}
  table.clear(items)
  bf:findAllObjects(items, ObjType.Barrier)
  for i,item in ipairs(items) do
    item:removeFromGame()
  end
end

function main()
  subscribe(Event.tick)

  object = WallItem.new()
  local geom = {}
  table.insert(geom, point.new(0,0))
  table.insert(geom, point.new(1,0))
  table.insert(geom, point.new(0,1))
  object:setGeom(geom)
  levelgen:addItem(object)
end