Flash

local n = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

function change(num)
    c = colors.black

    if num == 1 then
        c = colors.white
    elseif num == 2 then
        c = colors.orange
    elseif num == 3 then
        c = colors.yellow
    elseif num == 4 then
        c = colors.lime
    elseif num == 5 then
        c = colors.pink
    elseif num == 6 then
        c = colors.cyan
    elseif num == 7 then
        c = colors.purple
    elseif num == 8 then
        c = colors.blue
    elseif num == 9 then
        c = colors.red
    elseif num == 10 then
        c = colors.lightGray
    end

    term.setBackgroundColor(c)
    term.clear()
end

while true do
    change(math.random(1, #n))
    sleep(0.5)
end