[LUA]Matrix V2 [Preferred version]

term.redirect(peripheral.wrap("top"))
local chars = {}

local function new(t)
	t.y = 0
	table.insert(chars, t)
end

setmetatable(chars, {__call = function(t)
	local i = 0
	return function()
		i = i + 1
		return t[i], i
	end
end})

local function timer(period)
	return {
		id = nil;
		run = function(self)
			self.id = os.startTimer(period)
		end;
	}
end

local updateTimer = timer(0.1)
local creator = timer(0.1)

updateTimer:run()
creator:run()

term.setBackgroundColor(colors.black)
term.clear()
term.setCursorPos(1,1)

while true do
	local _, t = os.pullEvent('timer')
	local w,h = term.getSize()

	if t == updateTimer.id then
		for char, i in chars() do
			char.y = char.y + 1

			if char.y > h then
				table.remove(chars, i)
			else
				term.setCursorPos(char.x, char.y)
				if char.color == colors.black then
					term.setBackgroundColor(colors.black)
					term.write(' ')
				else
					term.setTextColor(char.color)
					term.write(string.char(math.random(38, 126)))
				end
			end
		end

		updateTimer:run()
	elseif t == creator.id then

		local time = math.random()*0.8 + 0.5
		local tail = timer(time)
		local eraser = timer(time + math.random()*0.25 + 0.5)

		new {
			x = math.random(w);
			color = colors.green;
			tail = tail;
			eraser = eraser;
			ishead = true;
		}

		creator:run()
		tail:run()
		eraser:run()
	else
		for char in chars() do
			if char.ishead then
				if t == char.tail.id then
					new {
						x = char.x;
						color = colors.green;
					}
					break
				elseif t == char.eraser.id then
					new {
						x = char.x;
						color = colors.black;
					}
					break
				end
			end
		end
	end
end