View difference between Paste ID: gvUMfX7H and KQjmtASU

 --(c) 2013 Felix Maxwell
 --License: CC BY-SA 3.0
 
 local fps = 8 --Determines how long the system will wait between each update
 local maxLifetime = 40 --Max lifetime of each char
 local minLifetime = 8 --Min lifetime of each char
 local maxSourcesPerTick = 5 --Maximum number of sources created each tick
 local sourceWeight = 0 --Affects the chance that no sources will be generated
 local greenWeight = 8 --Threshhold out of 10 that determines when characters will switch from lime to green
 local grayWeight = 2 --Same as about, but from green to gray
 
 function getMonitors()
 	local monitors = {}
 	if checkMonitorSide( "top" ) then table.insert( monitors, "top" ) end
 	if checkMonitorSide( "bottom" ) then table.insert( monitors, "bottom" ) end
 	if checkMonitorSide( "left" ) then table.insert( monitors, "left" ) end
 	if checkMonitorSide( "right" ) then table.insert( monitors, "right" ) end
 	if checkMonitorSide( "front" ) then table.insert( monitors, "front" ) end
 	if checkMonitorSide( "back" ) then table.insert( monitors, "back" ) end
 	return monitors
 end
 function checkMonitorSide( side )
 	if peripheral.isPresent( side ) then
 		if peripheral.getType(side) == "monitor" then
 			return true
 		end
 	end
 	return false
 end
 function printMonitorStats( side )
 	local x, y = peripheral.call(side, "getSize")
 	local color = "No"
 	if peripheral.call(side, "isColor") then
 		color = "Yes"
 	end
 	print("Side:"..side.." Size:("..x..", "..y..") Color?"..color)
 end
 function askMonitor()
 	local monitors = getMonitors()
 	if #monitors == 0 then
 		print("No monitors found, add more!")
 		return nill
 	elseif #monitors == 1 then
 		return monitors[1]
 	else
 		while true do
 			print("Multiple monitors found, please pick one.")
 			for i,v in ipairs(monitors) do
 				write("["..(i).."] ")
 				printMonitorStats( v )
 			end
 			write("Selection: ")
 			local sel = tonumber(io.read())
 			if sel < 1 or sel > #monitors then
 				print("")
 				print("Invalid number.")
 			else
 				return monitors[sel]
 			end
 		end
 	end
 end
 
 function printCharAt( monitor, x, y, char )
 	monitor.setCursorPos( x, y )
 	monitor.write( char )
 end
 function printGrid( monitor, grid, color )
 	for i=1,#grid do
 		for o=1,#grid[i] do
 			if color then monitor.setTextColor( grid[i][o]["color"] ) end
 			printCharAt( monitor, i, o, grid[i][o]["char"] )
 		end
 	end
 end
 
 function colorLifetime( life, originalLifetime )
 	local lifetimePart = originalLifetime/10
 	if life < grayWeight*lifetimePart then
 		return colors.gray
 	elseif life < greenWeight*lifetimePart then
 		return colors.green
 	else
 		return colors.lime
 	end
 end
 function getRandomChar()
 	local randTable = {"1","2","3","4","5","6","7","8","9","0","!","@","#","$","%","^","&","*","(",")","_","-","+","=","~","`",",","<",">",".","/","?",":","{","}","[","]","\\","\"","\'"}
 	return randTable[math.random(1, #randTable)]
 end
 function tick( screen )
 
 	--update lifetimes
 	for x=1,#screen do
 		for y=1,#screen[x] do
 			screen[x][y]["curLife"] = screen[x][y]["curLife"] - 1
 		end
 	end
 
 	--make the sources 'fall' and delete timed out chars
 	for x=1,#screen do
 		for y=1,#screen[x] do
 			if screen[x][y]["type"] == "source" and screen[x][y]["curLife"] == 0 then
 				screen[x][y]["type"] = "char"
 				screen[x][y]["lifetime"] = math.random(minLifetime, maxLifetime)
 				screen[x][y]["curLife"] = screen[x][y]["lifetime"]
 				screen[x][y]["color"] = colors.lime
 
 				if y < #screen[x] then
 					screen[x][y+1]["char"] = getRandomChar()
 					screen[x][y+1]["lifetime"] = 1
 					screen[x][y+1]["curLife"] = 1
 					screen[x][y+1]["type"] = "source"
 					screen[x][y+1]["color"] = colors.white
 				end
 			elseif screen[x][y]["curLife"] < 0 then
 				screen[x][y]["char"] = " "
 				screen[x][y]["lifetime"] = 0
 				screen[x][y]["curLife"] = 0
 				screen[x][y]["type"] = "blank"
 				screen[x][y]["color"] = colors.black
 			elseif screen[x][y]["type"] == "char" then
 				screen[x][y]["color"] = colorLifetime( screen[x][y]["curLife"], screen[x][y]["lifetime"] )
 			end
 		end
 	end
 
 	--create new character sources
 	local newSources = math.random( 0-sourceWeight, maxSourcesPerTick )
 	for i=1,newSources do
 		local col = math.random(1, #screen)
 		screen[col][1]["char"] = getRandomChar()
 		screen[col][1]["lifetime"] = 1
 		screen[col][1]["curLife"] = 1
 		screen[col][1]["type"] = "source"
 		screen[col][1]["color"] = colors.white
 	end
 
 	return screen
 end
 
 function setup( w, h )
 	local retTab = {}
 	for x=1,w do
 		retTab[x] = {}
 		for y=1,h do
 			retTab[x][y] = {}
 			retTab[x][y]["char"] = " "
 			retTab[x][y]["lifetime"] = 0
 			retTab[x][y]["curLife"] = 0
 			retTab[x][y]["type"] = "blank"
 			retTab[x][y]["color"] = colors.black
 		end
 	end
 	return retTab
 end
 function run()
 	local monitor = peripheral.wrap( askMonitor() )
 	local color = monitor.isColor()
 	local w, h = monitor.getSize()
 	local screen = setup( w, h )
 	while true do
 		screen = tick( screen )
 		printGrid( monitor, screen, color )
 		os.sleep(1/fps)
 	end
 end
 
 run()