Recessive genes are the only one that can have Hets. There are co-dominate genes, recessive, and dominate. A recessive gene only replicate themselves with the same recessive gene. For example: Het Pied x Het Pied = Visual Pieds
Or Pied x Pied = More awesome Pieds lol
So they will either have to be a visual of the recessive gene or a carrier of the gene to produce more visuals.
Try out this site and use the genetic wizard, it also has a nice section that explains geneticsI hope all that stuff I said makes sense. I suck at explaining things sometimes
http://www.worldofballpythons.com