I'm not sure if I've done the math properly. I took the code minus the loops and timed it, from start to finish it takes 0.08 secs, which doesn't sound like much, but when you multiply that by the resolution of mode 0 screen (160x200), it becomes 32000x0.08 = 2560. Divide 2560/60 and I get an result of 42.6666667 minutes.
Things to remember:
* BASIC is an Interpreted Language, which means everything has to be converted for the machine to understand, which takes time.
* Mandelbrots use Floating Point Numbers (Decimal Numbers), which aren't as fast as Integers (Whole Numbers).
* Compiled Languages such as Pascal may or may not be good with Mandelbrots depending on how good they handle the math. A comparision between Hisoft's Pascal 4t Vs. Turbo Pascal 3 had Hisoft Pascal well in front. A comparision chart was posted within these threads, though I'm unable to find it!
* Can be written in Assembly, though believe it to be difficult.