The Genera HACKS demonstration suite

Evidence and release boundaries

The release directory marks 440 as both the released and latest HACKS version. Its component directory was written on 30 September 1997 in an Open Genera 2.0 / Genera 8.5 environment on a 1280 by 976, eight-bit pseudocolor X screen. That records the build environment, not a minimum display requirement and not a claim about the current 24-bit Xvfb transport.

How the suite is assembled

The system declaration separates two jobs:

1. demo-definitions installs the eighteen text descriptors under SYS:SITE;.
2. Hacks loads shared menu/window definitions, eight bitmap fonts, those descriptors, and the implementation modules in parallel.

Every descriptor names Hacks as its required system and uses the suite's common legal-notice function. Referring to an unloaded demonstration first loads only its small descriptor. The first run then initializes it; initialization asks before loading any missing required system and loads accepted systems silently without further queries. Descriptor discovery therefore does not prove that the implementation is resident.

The modern facility exposes this complete command surface:

The 8.1 manual lists More Processing and Output Destination for Run Demonstration. The inspected later source explicitly suppresses the output- destination keyword and directly defines only Show Instructions and Specify Options. This is a manual/source difference, not silently normalized documentation.

ABACUS

ABACUS runs HACKS:ABACUS-DEMO. It opens a two-pane frame: a large graphical ten-column abacus and a small listener-like command pane. Each decimal digit is represented by one upper five-bead decision and one lower zero-through-four bead position. The window object is retained and reused on later invocations.

BIRDS

BIRDS calls HACKS:BIRDS-DEMO with a nonnegative Slowness value. It does not draw literal bird artwork. Each frame XORs two triangles that share two vertices. Four moving points advance at fixed rates in a 513-pixel square, with modular coordinates folded around the midpoint to produce billiard-like reflections.

The series contains five rate pairs for the third point—(2,3), (3,4), (16,24), (128,192), and (255,257)—while the fourth point swaps each pair. The two shared points use (1,1) and (2,2). A presentation ends at its repeat point; the series then waits before continuing.

CROCK

CROCK runs HACKS:CROCK-DEMO, an analog wall clock in a reusable square window. It draws a circular face with numerals 1 through 12, a thin second hand, and two filled irregular hand outlines. The hour hand is quantized to quarter hours, the minute hand to half minutes, and the second hand to seconds. Resizing recomputes the radius, hand scale, and numeral font.

The clock is also a chimer. At each half hour it plays a short lead-in and one bong; at an exact hour it plays the lead-in and bongs the displayed hour count. This audio behavior is in the implementation but absent from the descriptor summary.

DIGITAL-CROCK

DIGITAL-CROCK runs HACKS:DC-DEMO. A centered window shows HH:MM:SS using seven geometric strokes per digit and two fixed colons. The first hour digit is blank for single-digit hours. Unlike the analog face, the digit producer uses the hour returned by TIME:GET-TIME directly, so the source describes a 24-hour display.

Each update renders the old and new glyphs into temporary rasters, XORs them to obtain only the changed strokes, applies that delta to a retained image, and copies the result to the screen. This is a small demonstration of incremental raster updating as much as a clock.

ESCHER

ESCHER calls HACKS:ESCHER-DEMO. Two reflected points define a line segment; the program XORs that line and three mirror images, giving fourfold symmetry. As the endpoints advance and reflect, drawing the same pixel twice erases it, so changing lace-like line fields emerge without a retained scene model.

The five presentations use endpoint velocity pairs (2,1)/(4,3), (0,1)/(3,2), (1,2)/(2,3), (0,2)/(1,3), and (0,1)/(2,3). Each ends when its complete coordinate state returns to a repeat corner.

GODEL

GODEL exposes the single-line motion underlying Escher. It XORs one segment between two independently moving, reflected endpoints, with no fourfold copies. The result lets a viewer distinguish the trajectory generator from Escher's symmetry layer.

The media filename is GOEDEL.DEMO, but the descriptor symbol, displayed name, and implementation functions use GODEL. The spelling difference is preserved rather than “corrected.” Slowness defaults to 2048 busy-loop iterations.

HACKS

HACKS is the compatibility entry point HACKS:DEMO, not another visual algorithm. It opens the older mouse menu built by active DEFDEMO forms. The modern descriptor itself warns that this path is less instructive than running the individual descriptors.

The inspected build registers these seventeen top-level entries, sorted alphabetically at display time:

HOLLERITH-EDITOR

HOLLERITH-EDITOR calls HACKS:EDIT-MULTIPLE-CARDS. It draws an 80-column card marked as an IBM 5081, prints the entered characters across its top, and places rectangular holes in the appropriate row positions. After each nonblank card it shifts the previous screen image five pixels left and twenty pixels upward, then draws the next card, producing a visible stack.

LEXIPHAGE

LEXIPHAGE calls HACKS:LEXIPHAGE with a String option whose default is its own name. It centers that text in a short window using 43VXMS, pauses briefly, and moves a triangular upper jaw, lower jaw, and teeth from left to right. Alternating jaw depth creates a chewing motion, while erase triangles remove both the preceding mouth image and the text it has crossed.

There are no ordinary controls and no input poll. Once started, it runs to completion; an external Abort is the only early interruption path. The descriptor attributes the idea to John Doty. The implementation returns a small completion value that the demonstration facility does not display specially.

The System 46 scan-line version, maintained LM-3 triangle version, Genera relationship, PDP-10 antecedent, geometry, and attribution evidence are treated in LEXIPHAGE: a word-eating display hack. This page adds only the Genera descriptor default, restriction, and exact local implementation boundary.

LIFE

LIFE runs HACKS:RUN-LIFE, Conway's cellular automaton in a reusable 128 by 128 HOF window. The wrapper clears the window and draws one horizontal line through its vertical midpoint as the seed. Each computed generation is copied back to the window, and its zero-based generation counter is written at the home cursor.

The implementation represents the eight-neighbor count as three one-bit planes and two carry rasters. A sequence of BitBlts adds each shifted neighbor image, then keeps cells with three neighbors or live cells with two, while rejecting the four-or-more plane. The source comments describe 65 BitBlts per generation and a later revision that accepts either windows or raster arrays, accepts a generation limit, and handles multi-bit screens.

MUNCHING-SQUARES

MUNCHING-SQUARES runs HACKS:MUNCH with its implementation default of #o401 (257 decimal). It displays the current 16-bit parameter, a 16-switch register, a 256 by 256 raster, and an on-screen help pane. The accumulator repeatedly adds the parameter modulo 65536; the low byte is X and low-byte XOR high-byte is Y; the pixel at that location is toggled.

MUNCHING-TUNES

MUNCHING-TUNES feeds the arithmetic skeleton of Munching Squares into the beep facility instead of plotting pixels. It advances a modular accumulator by the magic constant, XORs the lower and upper portions to obtain a frequency value, shifts that value by Pitch, and emits one beep whose duration is Slowness.

QIX

QIX calls HACKS:QIX with a Length default of 64. Two independently wandering endpoints define one XOR line. Each endpoint's X and Y velocity performs a bounded random walk and reflects at the window edges. A circular history erases the line that is Length steps old, producing a moving cluster rather than an indefinitely filled screen.

ROTATE

ROTATE runs HACKS:RUN-ROTATE. It first draws a radial fan from the upper-left corner and places a large italic Symbolics label near the center. On request it copies a fixed 512 by 512 region into a temporary one-bit raster and rotates that raster clockwise in place.

The algorithm repeatedly halves a quadrant mask. Each of the nine levels for a 512-pixel image performs fifteen BitBlts and redisplays the intermediate raster. The descriptor states the general count as 2 + 15*log2(N), or 137 BitBlts for 512, and records about five seconds on its historical target. That timing is not applied to the current VLM.

SPLINES

SPLINES runs HACKS:SPLINES-IN-WINDOW, selecting a reusable drawing window inset slightly from the screen edges. It gathers pointer-selected control points and calls the window's cubic-spline primitive either in relaxed open mode or cyclic closed mode. Control-point dots are removed before the curve is drawn; completed curves remain, so multiple independent curves accumulate until exit.

TV-BUG

TV-BUG calls HACKS:TVBUG. It starts a 32 by 32 creature near the bottom center of the chosen sheet and advances it upward one pixel per animation phase. Four embedded one-bit frames provide the walking poses. The implementation precomputes XOR first-difference rasters that both move and change the creature without redrawing the entire window.

WORM

WORM draws layered fractal paths attributed by the descriptor to Gosper and Holloway. It first runs a large glyph along a recursive terdragon path to find and paint an initial surface. It then presets six cooperative stack groups at staggered positions. Their WORM-font glyphs use different raster operations—paint, erase, XOR, and combinations—so successive paths carve stripes, gray regions, and black regions into that surface.

The descriptor exposes no options, but the implementation entry defaults to bit selector 0, recursion order 7, and an octal-coordinate starting point. Generation labels and numeric command prefixes use base 9, a source-visible fact not stated in the descriptor prose.

ZOWIE

ZOWIE is a short sound-only demonstration. It sends a fixed compact note-and-tempo string to HACKS:PLAY-STRING; that interpreter maps keyboard-like note letters to an equal-tempered scale, treats repeated letters as longer notes, and recognizes rests and tempo changes. Zowie resets the common speed first, changes it within the phrase, and returns when the fixed sequence is exhausted.

There are no ordinary controls and the phrase does not poll for input. The descriptor says only to listen and describes the effect as the sound of a presidential hotline in the “Flint” movies. This article preserves that descriptor attribution without guessing a specific film, recording, or musical quotation.

The local-screen and local-terminal restrictions are both present even though the entry produces no designed visual state. Their historical rationale is unknown. A meaningful runtime test must establish whether the identified VLM exposes audible beeps; a screenshot would not document this program's substantive output.

Findings not evident from the descriptor prose

Several suite-wide conclusions come from implementation inspection rather than the manual summaries:

• many programs document End or Space but actually treat any character as stop, continue, rotate, or pause input;
• Abacus has a complete mouse bead editor and ten-digit modular arithmetic;
• both clocks can chime, and the digital clock uses incremental stroke deltas;
• the legacy HACKS menu contains exactly the seventeen individual programs, while several tempting DEFDEMO strings survive only inside comments;
• Godel uses one moving XOR segment, while Escher adds fourfold reflection and Birds adds two shared-base triangles;
• Munching Tunes and Zowie have no intended visible animation despite local-screen restrictions;
• Splines accepts End, ignores consecutive duplicate points, and accumulates completed curves;
• TV Bug stores four animation frames as source rasters rather than a font; and
• Worm's visible generation and numeric command language are base 9.

These findings are release-bounded. They do not establish that a site patch, a different HACKS release, or a physical Symbolics console behaved identically.

Complete animation coverage

The target is one complete bounded runtime animation for every descriptor: actual invocation, enough ordinary operation to establish its visible behavior and controls, and the real stop or exit. A still, two unrelated endpoint frames, or descriptor prose is not a runtime animation. The present Genera 8.5 world cannot load HACKS 440, so none of the following rows is represented as recorded.

The tracked recorder/curator accepts only raw material from one coherent local harness session. It cannot manufacture these clips from the licensed descriptors, the CADR counterparts, or unrelated Genera stills.

Runtime observation and screenshot status

Session d58-hacks-20260718, generation 1, started at 2026-07-18T11:54:37-04:00 on a private 1200 by 900 X client. The Listener reported an X-SCREEN::X-REAL-SCREEN with 1200 by 852 usable pixels and SYS:REMOTE-TERMINAL-P = NIL. A read-only probe then established:

• package HACKS existed, but SCT:GET-SYSTEM-VERSION "Hacks" returned NIL;
• SCT:FIND-SYSTEM-NAMED found no loaded HACKS system;
• HACKS:DEMO, ABACUS-DEMO, CROCK-DEMO, MUNCH, QIX, WORM, and ZOWIE had no symbols or function bindings in that package;
• the loaded-demonstration hash table contained zero entries; and
• querying SYS:SITE;*.DEMO.NEWEST reached the world's Please login prompt because the world was not configured for a local site and the sandbox exposes no file service.

The first raw evidence capture is 1200 by 900 pixels, PNG SHA-256 9a34c290a4692c1797ba95df7a6c53369098171b83f5ddb5cbf9db8238db19b2, pixel SHA-256 1127907f205c8663a2f8f1e09a290e967020a8b0f7e7d8475fecdf8dc1a268ae, after action log count 2 and action-log hash e892f6ba4ae0b79481c449401212c0c6ca8712f68394d9dae4eb6fa14af3f550. It is retained only in the ignored session tree.

No screenshot is published on this page. The captures show a generic Dynamic Lisp Listener and a site-login prompt, not one of the programs documented here; publishing one would be decorative rather than evidence of HACKS behavior. The exact blocker is the absent loadable system plus inaccessible SYS:SITE descriptor path. A future capture requires a disposable, isolated, rights-compatible way to expose the exact licensed HACKS media to the guest, followed by an image-specific review under the screenshot publication policy.

Shutdown reached the VLM prompt, sent and accepted confirmation, and observed cleanup progress, then encountered the known cleanup stall and required bounded force. The final record is forced-stopped, state_may_be_incomplete = true, and not orderly. The base and private worlds were unchanged. save_world_performed and guest_checkpoint_created remain unknown; the harness created no host checkpoint.

Open questions and next runtime work

• Load HACKS 440 into a fresh private world through a minimal read-only media path without turning the harness into a configured Symbolics site.
• Recheck the local-screen-only predicate on the actual X real screen once a descriptor is loaded; screen type alone is not the predicate result.
• Exercise the digital clock's noon/midnight chime edge instead of resolving it from code inspection alone.
• Confirm whether all “any character” exits behave as the source indicates through the current X key translation.
• Record one complete bounded interaction for every descriptor in the ledger above, while keeping each clip limited to launch, behavior/controls, and stop rather than creating a decorative or indefinite gallery.
• Test the two sound-only entries with an auditable audio path; screenshots cannot prove that Munching Tunes or Zowie was heard.

Local artifact provenance

Paths below use Genera logical names so the record is portable. The byte counts and hashes identify the licensed local inputs without publishing them.

Sources

• Symbolics, Genera 8.1 Release Notes, pages 88–94, demonstration facility; verified 2026-07-18. Local PDF: 1,020,591 bytes, SHA-256 4b26763c71ada2ddd3dc4019e83f70df9ff242857a99e5d5326ca68f0be23225.
• Symbolics, Genera 8.3 Software Installation Guide for UX Family Machines, page 28, Hacks installation; verified 2026-07-18. Local PDF: 498,160 bytes, SHA-256 f8c09d757e08c65094676b76f5ad8d2e95d4b1309962c60cf26d463e57c2a126.
• Symbolics, Genera 8.3 Software Installation Guide for 3600 Family Machines, page 31, corroborating Hacks installation; verified 2026-07-18. Local PDF: 543,814 bytes, SHA-256 e30becd77fcf4e1491c1377cbed452eaaaf05efa4965843e72f5b06108b46551.
• LM-3, HACKS system declaration, and the maintained demo source tree, check-in 4df393c68d7f083ce42d5c377039d26043cc18a9031ace28258dc97f4137eb91; verified 2026-07-18.
• MIT CADR System 46, LMIO1; HACKS 189, commit 8e978d7d1704096a63edd4386a3b8326a2e584af; historical source for several antecedent display and sound hacks; verified 2026-07-18.
• Repository companion studies: MUNCH and Munching Squares, LEXIPHAGE, Genera font catalog, and Genera computer-use harness.