local function shuffle(l)
    for i = 1, #l do
        local new_i = math.random(1, #l)
        local tmp = l[new_i]
        l[new_i] = l[i]
        l[i] = tmp
    end
end

local function table_str(t)
    local str = "{"
    for _, v in pairs(t) do
        if type(v) == "string" then
            v = '"' .. v .. '"'
        end
        str = ("%s %s,"):format(str, v)
    end

    str = str .. " }"

    return str
end

local function test(l)
    local str = ("%s -> "):format(table_str(l))
    shuffle(l)
    str = str .. table_str(l)
    print(str)
end

math.randomseed(os.time())

test({ 1, 2, 3, 4 })
test({ "a", "b", "c", "d" })