local mon = peripheral.find("monitor")
if not mon then
    print("No monitor found!")
    return
end

mon.setTextScale(0.5)
mon.setBackgroundColor(colors.white)
mon.clear()

local w, h = mon.getSize()
local tiles = {}

local function initTiles()
    for y = 1, h do
        tiles[y] = {}
        for x = 1, w do
            tiles[y][x] = false
        end
    end
end

local function drawTiles()
    for y = 1, h do
        mon.setCursorPos(1, y)
        for x = 1, w do
            if tiles[y][x] then
                mon.setBackgroundColor(colors.gray)
            else
                mon.setBackgroundColor(colors.lightGray)
            end
            mon.write(" ")
        end
    end
end

local function carveWave()
    local col = math.random(1, w)
    for row = 1, h do
        tiles[row][col] = true
        local r = math.random(3)
        if r == 1 and col > 1 then
            col = col - 1
        elseif r == 3 and col < w then
            col = col + 1
        end
    end
end

local function fadeTiles()
    for y = 1, h do
        for x = 1, w do
            if math.random(100) < 2 then
                tiles[y][x] = false
            end
        end
    end
end

initTiles()

while true do
    carveWave()
    fadeTiles()
    drawTiles()
    sleep(0.05)
end