by Chetil
The cubes sold in BGG Store for the Space Alert Upgrade Set are quite similar. I think you get 24 green cubes in that set, so 2 set should be enough for a "bunch" of cubes that comes with KoT (my copy came with 50 cubes).The original cubes are slightly darker in color, and I think they look better, but this is a decent alternative if Iello can't help you out.