WITCH lboxy: Revision 5
"box", "array", "square"
Used as a brace pair or quote pair
 in a term treats it as an array
Operators containing this character
When used inside regexes
As an adverb
 after an adverb can assign an Array object to an adverb
Hyper operator and meta operator restrictions
When used as the reduce meta-operator, only certain reducer operations have identity, others require multiple elements.
Old, deprecated, or other language uses