DEEP MAGIC

[possibly from C. S. Lewis's "Narnia" books] An awesomely arcane technique central to a program or system, especially one neither generally published nor available to hackers at large (compare black art ); one that could only have been composed by a true wizard . Compiler optimisation techniques and many aspects of OS design used to be deep magic ; many techniques in cryptography, signal processing, graphics, and AI still are. Compare heavy wizardry . Especially found in comments of the form "Deep magic begins here.". Compare voodoo programming .