Master4

-- Number of neighbouring turtles
numberNeighbours = 2

-- Open up modem to receive wireless broadcasts
rednet.open("right")

-- Wait until neighbouring turtles are ready
function waitForNeighbours(localRowsProgressed)
  local remoteTurtleID, remoteRowsProgressed

  -- Wait for all neighbours to have done same number of rows as master
  for i=1, numberNeighbours do
    repeat
      -- Find how many rows the current remote turtle has done
      remoteTurtleID, remoteRowsProgressed, _ = rednet.receive()
      remoteRowsProgressed = string.match( remoteRowsProgressed, "ROW<%d+>" )
      remoteRowsProgressed = string.match( remoteRowsProgressed, "%d+" )
      remoteRowsProgressed = tonumber( remoteRowsProgressed )

      -- If this is a valid rednet message, and remote turtle is lagging behind, tell him to continue
      if (remoteRowsProgressed ~= nil) and (remoteRowsProgressed < localRowsProgressed) then
        rednet.send(remoteTurtleID, "You are authorised to proceed")
      end

    until localRowsProgressed == remoteRowsProgressed
  end

  rednet.broadcast("You are authorised to proceed")
end

bool=true

while bool==true do
  if rs.getInput("back", true) then
      print ("Waiting")
      sleep (1)
  else
    print ("Let's Roll!")
    bool=false
  end
end

X=3

print ("Startup Functions Activating")
print ("Going to lowest point")

turtle.select(3)
turtle.back()

for a = 1, X do
  turtle.digDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.attackDown()
  turtle.down()
end

for b = 1, X do
  turtle.digUp()
        while not turtle.up() do
                turtle.attackUp()
        end
end

print ("Calibrated level for a flat bedrock world.")
print ("---------------------------")
print ("Starting World Eating Scripts!")
print ("---------------------------")

turtle.dig()

while not turtle.forward() do
  turtle.attack()
end

while true do

for i = 1, 2 do

  for c = 1, X do
    turtle.dig()
    turtle.digDown()
        while not turtle.down() do
                turtle.attackDown()
        end
  end

  for d = 1, X do
    turtle.dig()
    turtle.digUp()
        while not turtle.up() do
                turtle.attackUp()
        end
  end

for r = 1, 2 do
        turtle.dig()
        while not turtle.forward() do
                turtle.attack()
        end

end

Fuel = turtle.getFuelLevel()

print ("Fuel level is: "..Fuel)

if Fuel >= 8192 then

  print ("Fuel level is above minimum safe limit.")
print ("Refueling anyway")

  turtle.select(1)

  for slot = 3, 16 do
    result = turtle.compareTo(slot)
    if result == true then
      turtle.select(slot)
      turtle.refuel()
      turtle.select(1)
      print ("Refueled on slot "..slot)
    else
    end
  end

else

  print ("Fuel is below safe limit! Not collecting enough coal!")

  turtle.select(1)

  for slot = 3, 16 do
    result = turtle.compareTo(slot)
    if result == true then
      turtle.select(slot)
      turtle.refuel()
      turtle.select(1)
      print ("Refueled on slot "..slot)
    else
    end
  end
end

turtle.select(2)
print ("Dropping off items")

turtle.dig()

while not turtle.place() do
        turtle.attack()
end

for dropslot = 3, 16 do
  turtle.select(dropslot)
  turtle.drop()
end

waitForNeighbours()

turtle.select(2)

turtle.dig()

turtle.select(3)

end
end