failed lua sudoku generator

--[[
	Attempt at sudoku
	by BigShinyToys
]]--
local testMode = false

local function dPrint(...)
	print(...)
	sleep(0.5)
end

if not testMode then
	dPrint = function()
	end
end

local function generate()
	local valed = true
	local loop = true
	local line = {}
	local column = {}
	local game = {}
	local box = {
		{{},{},{},},
		{{},{},{},},
		{{},{},{},},
	}
	for x = 1,3 do
		for y = 1,3 do
			for pos = 1,9 do
				box[x][y][pos] = true
			end
		end
	end
	for x = 1,9 do
		line[x] = {}
		column[x] = {}
		for y = 1,9 do
			line[x][y] = true
			column[x][y] = true
		end
	end

	for x = 1,9 do
		game[x] = {}
		for y = 1,9 do
			local possible = {}
			for slot = 1,9 do
				dPrint(tostring(x).." "..tostring(math.ceil(x/3)).." "..tostring(y).." "..tostring(math.ceil(y/3)))
				if line[x][slot] and column[y][slot] and box[math.ceil(x/3)][math.ceil(y/3)][slot] then
					table.insert(possible,slot)
				end
			end
			--print(#possible)
			if #possible ~= 0 then
				local slot = possible[math.random(1,#possible)]
				game[x][y] = slot
				line[x][slot] = false
				column[y][slot] = false
				box[math.ceil(x/3)][math.ceil(y/3)][slot] = false
			else
				valed = false
			end
		end
	end

	return game,valed
end

local function drawGame(game,offX,offY)
	local setX = offX or 0
	local setY = offY or 0
	for x = 1,9 do
		for y = 1,9 do
			term.setCursorPos((x*3) + setX,(y*2) + setY)
			term.write(tostring(game[x][y]))
			sleep(0.1)
		end
	end
end

while true do
	term.clear()
	local loop = 1
	local myGame,valed = generate()
	while not valed do
		loop = loop + 1
		myGame,valed = generate()
	end
	print(loop)
	drawGame(myGame)
	local _,n = os.pullEvent("key")
	if n == 200 then
		break
	end
end