Handicap

"Perverse" problems, that place some arbitary handicap on the programming.

E.g.

Source must be in uppercase only : CALENDAR
Not allowing certain datastructures: strings/arrays/... : Odd word problem
Restricted I/O
No comparisons, arithmetic, no lists, no re-reading of input : Longest string challenge‎
Code golf challenges : Game of Nim
The task to be solved depends on the source of the program itself : Quine, Narcissist

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