Arella Rockstar is inbred 4x5 to Fappiano and to Hold Your Peace through Quiet Eclipse, dam of Astrology, and Old Fashioned, sire of Arella Rockstar's dam Story Untold. The two are bred on rather similar lines, as Quiet Eclipse is by a son of Fappiano out of a Hold Your Peace mare while Old Fashioned is by a grandson of Fappiano out of a granddaughter of Hold Your Peace. More important, perhaps, is the reinforcement of the bloodlines that created Fappiano in other parts of the pedigree.
One of the best horses that John Nerud bred in his own name, Fappiano was sired by Mr. Prospector from the mare Killaloe, a daughter of the great Dr. Fager and a granddaughter of Tartan Farms foundation mare Cequillo. Dr. Fager, in turn, was produced from the mating of Rough'n Tumble with Tartan Farms' other foundation mare, Aspidistra, whose great-granddaughter Gana Facil produced champion Unbridled when mated to Fappiano. Unbridled, in turn, sired Unbridled's Song, sire of Old Fashioned.
Astrology carries a still more concentrated dose of these same bloodlines through his broodmare sire Quiet American, who was sired by Fappiano from Demure, by Dr. Fager. As Demure was produced from a daughter of Cequillo, Quiet American is inbred 3x2 to Dr. Fager and 4x3 to Cequillo.
The final strands in the design of Arella Rockstar's pedigree are supplied by her second dam, Shappy, who was sired by the In Reality horse Really Secret from the Dr. Blum mare Salt in My Stew. While none of these names are exactly household icons (though In Reality was quite a good racer and sire), they are significant in this context. In Reality is out of My Dear Girl, a champion daughter of Rough'n Tumble, while Dr. Blum is a son of Dr. Fager. Thus, Arella Rockstar's pedigree blends line breeding to Dr. Fager, Rough'n Tumble, Cequillo and Aspidistra. No one of these elements may be very significant when taken alone but taken together, they represent a cluster of bloodlines that have proven compatible in the past and could reasonably be expected to prove so again. That they combined in this case to produce a nice filly from a relatively modest pedigree is still luck, but luck that had the boost of intelligence and study behind it.