local size = 100
local offsetH, offsetW = love.graphics.getHeight() / 2 - 250, love.graphics.getWidth() / 2 - 250

local grid = {
    {false, false, false, false, false},
    {false, false, false, false, false},
    {false, false, false, false, false},
    {false, false, false, false, false},
    {false, false, false, false, false},
}

function flip(x, y)
    if grid[y] ~= nil and grid[y][x] ~= nil then
        grid[y][x] = not grid[y][x]
    end
end

function toggle(x, y)
    flip(x, y + 1, grid)
    flip(x + 1, y, grid)
    flip(x, y, grid)
    flip(x - 1, y, grid)
    flip(x, y - 1, grid)
end

function love.load()
    math.randomseed(os.time())
    for i = 1, 20 do
        toggle(math.random(1, 5), math.random(1, 5))
    end
end

function love.draw()
    for y = 1, 5 do
        for x = 1, 5 do
            if grid[y][x] then
                love.graphics.rectangle("fill", (x - 1) * size + offsetW, (y - 1) * size + offsetH, size, size)
            else
                love.graphics.rectangle("line", (x - 1) * size + offsetW, (y - 1) * size + offsetH, size, size)
            end
        end
    end
end

function love.mousepressed(x, y, button)
    local gridx = math.floor((x - offsetW) / size) + 1
    local gridy = math.floor((y - offsetH) / size) + 1
    toggle(gridx, gridy)
end