Alchemist Turtle: 2x2 Crafting Sand to Sandstone

turtle.select(4)
slotcl=1
countcl=0

print("2x2 Crafting")
print("Input:  Down-Chest: Sand")
print("Output: Up-Chest:   Sandstone")

while true do

slota=turtle.getItemSpace(2)
slotb=turtle.getItemSpace(5)
slotc=turtle.getItemSpace(6)
slotd=turtle.getItemSpace(1)

 turtle.suckDown()
 turtle.transferTo(2, slota)
 turtle.dropDown()
 turtle.suckDown()
 turtle.transferTo(5, slotb)
 turtle.dropDown()
 turtle.suckDown()
 turtle.transferTo(6, slotc)
 turtle.dropDown()
 turtle.suckDown()
 turtle.transferTo(1, slotd)
 turtle.dropDown()

 slotcl=1
 countcl=0
 for asas=1, 16 do
  countcl = countcl + turtle.getItemCount(slotcl)
  slotcl=slotcl+1
 end

 if countcl==256 then
  turtle.select(4)
  turtle.craft()
  turtle.dropUp()
 else
 print("sleep")
 sleep(2)
 end
end