Beyond the Tesseract

Early (1983) TRS-80 BASIC text adventure game, the middle in a forgotten
trilogy (sandwiched between “Project Triad” and “Codename Intrepid”),
remembered for its no-holds-barred approach to math and logic concepts
informing game settings and puzzles: in one section, sparking a genre cliche,
one has to play a text adventure game inside the text adventure game ; in
another, one falls asleep and in a dream constructs a proof utilising physical
representations of various components of symbolic logic; additional game areas
are accessed by pushing and popping the stack, objects extruded from 2 to 3
dimensions by y ing them.

The supporting documentation understates when it claims the scenario for the
adventure is meant to be vague — searching for a 12-word code phrase
(unlocked in chunks upon completion of certain puzzles) is just an excuse for
sending an unwary player through an alien and abstract setting two words at a
time (using VERB NOUN gameplay with a vocabulary of about 200).

Later (1988) versions of this game were ported in C to Solaris, Atari ST and
MS-DOS environments; more recently, in December 2003, Andrew Plotkin ported it
to the interactive fiction standard of machine-independent Z-code.

Beyond the Tesseract