minetest_basic_robot_write_message.lua

p = self.spawnpos()

str="THIS IS THE MESSAGE!"

isx = 1
isz = 0
dir = -1

for i = 1, #str do
  local c = str:sub(i,i)

  minetest.set_node({
    x=p.x + (i * dir) * isx,
    y= p.y + 3,
    z=p.z + (i * dir) * isz
   }, { name="basic_robot:button_" .. string.byte(c) })

end

self.remove()