SingleCurve

os.loadAPI("tt")

curve = fs.open("curve1","r")
cur = curve.readLine()
x = 0
y = 0
for a = 1,#cur do
  c = string.sub(cur,a,a)
  if c == "F" then
    turtle.forward()
    x = x + 1
  end
  if c == "P" then turtle.placeDown() end
  if c == "R" then turtle.digDown() end
  if c == "U" then
    turtle.up()
    y = y - 1
  end
  if c == "D" then
    turtle.down()
    y = y + 1
  end
  if c == "B" then
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.place()
    turtle.turnLeft()
    turtle.turnLeft()
  end
  tt.restock()
end

turtle.turnLeft()
turtle.turnLeft()
for a = 1,y+1 do
  turtle.up()
end
for a = 1,x do
  turtle.forward()
end
turtle.turnRight()
turtle.forward()
turtle.turnRight()
turtle.down()