toy test (cc)

local scr_x, scr_y = term.getSize()
local screen = {}
local resetScreen = function()
    screen = {}
    for a = 1, scr_y do
        table.insert(screen,string.rep("0",scr_x))
    end
end

substrReplace = function(str,x,char)
    if not char and x then return str end
    if not str then return end
    return str:sub(1,x-1)..char..str:sub(x+1)
end

local getchar = function(x,y)
    if not screen[y] then return -1 end
    if x > #screen[y] then return -1 end
    return tonumber(screen[y]:sub(x,x)) or screen[y]:sub(x,x)
end

local setchar = function(x,y,char,scr)
    if not scr[y] then return end
    if x < 1 or x > #scr[y] then return end
    scr[y] = substrReplace(scr[y],x,char:sub(1,1))
end

local scrcols = {
    ["0"] = colors.black,
    ["1"] = colors.gray,
    ["2"] = colors.lightGray,
    ["3"] = colors.white,
}

local render = function()
    for y = 1, #screen do
        for x = 1, #screen[y] do
            term.setCursorPos(x,y)
            term.setBackgroundColor(scrcols[getchar(x,y)] or colors.black)
            term.write(" ")
        end
    end
end

local tn = tonumber
local ts = tostring

local proceed = function()
    local output = {} for a = 1, #screen do output[a] = screen[a] end
    for y = 1, #screen do
        for x = 1, #screen[y] do
            local num = tn(getchar(x,y))
            if num > 0 then
                setchar(x,y,ts(num-2),output)
                setchar(x+1,y,ts(getchar(x+1,y)+1),output)
                setchar(x-1,y,ts(getchar(x-1,y)+1),output)
                setchar(x,y+1,ts(getchar(x,y+1)+1),output)
                setchar(x,y-1,ts(getchar(x,y-1)+1),output)
            end
        end
    end
    for a = 1, #output do screen[a] = output[a] end
end


resetScreen()
local input = function()
    while true do
        local evt = {os.pullEvent()}
        if evt[1] == "mouse_click" then
            setchar(evt[3],evt[4],"2",screen)
        end
        if evt[1] == "key" then
            if evt[2] == keys.q then return end
            if evt[2] == keys.space then resetScreen() end
        end
    end
end

local game = function()
    while true do
        proceed()
        render()
        sleep(0.1)
    end
end

term.clear()

parallel.waitForAny(game,input)