sideWalkFiller

local fillInt = false
local fillExt = false
local squareSize = 7
local pause = 60

function compactInv()
  for i = 1,16 do
    if turtle.getItemCount(i) > 0 and turtle.getItemCount(i) < 64 then
      turtle.select(i)
      for j = i+1,16 do
        if turtle.compareTo(j) then
          turtle.select(j)
          turtle.transferTo(i)
          turtle.select(i)
        end
      end
    end
  end

  for i = 1,16 do
    if turtle.getItemCount(i) > 0 then
      for j = 1,i do
        if turtle.getItemCount(j) == 0 then
          turtle.select(i)
          turtle.transferTo(j)
          break
        end
      end
    end
  end
end

function checkItems()
  if ( turtle.getItemCount(1) < 2 ) then
    compactInv()
    turtle.select(1)
  end
end

function fill(size, interior, exterior)
  for side = 1, 4 do
    for i=1, (size-1) do
      turtle.move("front")
      checkItems()

      if interior then
        turtle.turnRight()
        if not turtle.detect() then
          turtle.place()
        end
        turtle.turnLeft()
      end

      if exterior then
        turtle.turnLeft()
        if not turtle.detect() then
          turtle.place()
        end
        turtle.turnRight()
      end
    end
    turtle.turnRight()
  end
end

while true do
  turtle.select(1)
  fill(squareSize, fillInt, fillExt)
  sleep(pause)
end