GauBricks v0.3

local dim = 16
local totalBlocks = 0
local selection = 1
local outOfBlocks = false
turtle.select(1)

function setTotalBlocks()
  local count = 1
  while ( count <= 15 and turtle.getItemCount(count) > 1) do
    totalBlocks = count
    count = count + 1
  end
end

function selectBlock()
  if ( outOfBlocks ) then return false end
  if ( turtle.getItemCount(selection) < 1 ) then
    if ( selection >= totalBlocks ) then
      outOfBlocks = true
      return false -- out of placeable blocks
    end
    selection = selection + 1
    turtle.select(selection)
  end
  return true

end

function checkSpace()
   if ( selectBlock() ) then
     if ( turtle.compareDown() == false ) then
       local needNewBlock = ( turtle.getItemCount(selection) == 1 )
       turtle.digDown()

       if ( outOfBlocks == false ) then turtle.placeDown() end
       if ( needNewBlock ) then
         if ( selection < totalBlocks ) then
           selection = selection + 1
           turtle.select(selection)
         else
           outOfBlocks = true
         end
       end
     end
   else
     turtle.select(16)
     if ( turtle.compareDown() == false ) then turtle.digDown() end
   end
end

function forward()
   if ( turtle.forward() == false ) then
     repeat
       os.sleep(3)
     until ( turtle.forward() == true )
   end
end

function checkAllTiles()
   local x,y = 0,0
   for x = 1,dim do
     for y = 1,dim do
       checkSpace()
       forward()
     end
     if ( x % 2 == 0 ) then
       turtle.turnLeft()
       forward()
       turtle.turnLeft()
     else
       turtle.turnRight()
       forward()
       turtle.turnRight()
     end
     forward()

   end

end


if ( turtle.detectDown() ) then turtle.up() end
setTotalBlocks()
while true do
  checkAllTiles()
  turtle.turnLeft()
  forward()
  os.Sleep(60)
end