count on an array : it works but it may be simpler ?

Not much to localize here, only one thing:

local papier = {} local ext = ".png" for i = 1, 5 do local page = {} papier[i] = page for k = 1, 2 do page[k] = "paper" .. (i-1)\*2+k .. ext end end

If the size of your second loop is constant you can optimize even more. But I think it isn’t worth the lossed flexibility.

local papier = {} local ext = ".png" for i = 1, 5 do local page = { "paper" .. (1-1)\*2+k .. ext, "paper" .. (2-1)\*2+k .. ext, } papier[i] = page end