I don't think all aspects of cubed have been figured out with 100% certainty, but it seems that the prevailing theory is that cubes are a variation within the homozygous stripe condition. I don't think the exact nature of its heredity has been established either. Two striped parents may produce a clutch with a mix of full four-lined stripes and cubed individuals. So a cubed het butter x cubed het butter pairing would yield the following (keep in mind that any animals listed as homo striped MAY be cubed):
25.00%, Striped, Het for Butter
12.50%, Caramel, Striped, Het for Amel
12.50%, Amelanistic, Striped, Het for Caramel
12.50%, Striped, Het for Caramel
12.50%, Striped, Het for Amel
6.25%, Butter, Striped
6.25%, Caramel, Striped
6.25%, Amelanistic, Striped
6.25%, Striped