Alessandro Rosa
Freelance programmer
c/o Locatelli,
Via Cappuccini 116/A,
I-72100 Brindisi, Italy
After explaining the details of an efficient technique, developed in early 1980s, to plot digital images of quaternion filled-in Julia sets, later considerations on it will introduce a new modification for displaying such sets with no interior too. A step by step description via pseudo-C++ is given. The reader is assumed to be familiar with advanced programming and quaternion calculus.