a humorous anecdote or remark intended to provoke laughter; "he told a very funny joke"; "he knows a million gags"; "thanks for the laugh"; "he laughed unpleasantly at hisown jest"; "even a schoolboy's jape is supposed to have some ascertainable point"
Jape is a configurable graphical, formal-proof calculator. It allows user to define a logic, decide how to view proofs, and much more. It works with variants of the sequent calculus and natural deduction.