CC fireplace

local screen = peripheral.wrap('back')

local fire = {}

local w,h = screen.getSize()
local max = math.ceil(h*0.5)

for i=1, w do
  table.insert(fire, math.random(max))
end

while true do
  screen.clear()

  for i=1, #fire do
    local n = fire[i]
    if n >= max then
      fire[i] = 1
    else
      fire[i] = n + math.random(0,2)
    end

    n = fire[i]

    for y=1, n do
      screen.setCursorPos(i, h - n + y)
      screen.write('S')
    end
  end

  sleep(0.1)
end