More BASIC Computer Games (1979, David H. Ahl)

Author(s): Edited by David H. Ahl; program conversion by Steve North (with Steven Neitz, Bruce Schaeffer, Jeff Yuan); illustrations by George Beker; introduction by Chris Cerf. Individual games by named contributors (Jeff Kenton, Vincent Erickson, Gary Lorenc, Richard Galbraith, and others). Sources: The book itself (Workman Publishing / Creative Computing, copyright 1979, first printing June 1980, ISBN 0-89480-137-6), read from a scan of the print edition. Line-number citations refer to the printed listings. Category: inspiration, Batch 12 (BASIC-listing corpus mining). Six games read in full. Cross-cutting cart mapping lives in ../synthesis-basic-games.md. Serves: runtime / engineering (assigned by Josh; see cart map)

What it is

More BASIC Computer Games is the second volume, and it is where the anthology’s programs get bigger and more systemic. Where the first book’s strength was tight, single-idea mechanics, this one carries several genuinely large simulations (Seabattle runs to eight printed pages) alongside sharper puzzle designs. The introduction by Chris Cerf frames the whole enterprise as computing-as-creative-medium rather than computing-as-tool, which is the same argument the KN-86 makes about a Lisp deck.

Six games were read for this capture, chosen because each extends a mechanic the first book established: Blackbox, Convoy, Geowar, Grand Prix, ICBM, Seabattle.

Mechanics

Read from the printed listings and sample runs. Line numbers cite the listings as printed.

• Blackbox (p.10): a computerized port of the Black Box pencil puzzle (Games and Puzzles, Aug 1977; program and writeup by Jeff Kenton). Atoms hide in an 8×8 grid; you fire rays from numbered edge ports (1-32, counterclockwise from the top of the left edge) and get one of three outcomes: ABSORBED, REFLECTED, or “TO <exit port>”. The implementation is the interesting part: each step advances one cell and inspects three cells (the one dead ahead plus the two diagonally flanking the direction of travel, lines 290-300), then packs them into an index 8*B(X1,Y1) + 2*B(X2,Y2) + B(X3,Y3) + 1 and dispatches (line 310). Direct hit absorbs; one diagonal neighbor deflects 90°; two diagonal neighbors reflect. All behavior falls out of local three-cell adjacency evaluated once per step, with no global path solver. Scoring is 1 point per reflection or absorption, 2 per emerging ray, 5 penalty per wrongly-guessed atom. Atoms can mask each other, so a position is occasionally genuinely ambiguous.

• Seabattle (p.143): a large submarine simulation by Vincent Erickson. You command a sub in a 20×20 area and must destroy a randomized enemy fleet (S=INT(RND*16)+15, line 440). Ten commands dispatch from an ON...GOTO (line 920): navigation, sonar, torpedo, Polaris missile, depth change, status, headquarters resupply, sabotage, power conversion, surrender. Resources are real: 6000 power units, 2500 lbs rocket fuel, 10 torpedoes, 3 missiles, 30 crew, and a depth reading. The world is an integer array A(20,20) seeded with terrain codes (land, enemy ship, headquarters, mine, sea monster). An enemy movement pass (from line 5210) steps every ship and resolves collisions against terrain, so a ship that walks onto a mine dies and one that meets a sea monster is eaten. The hazards kill the enemy too. The sonar map render (from line 1800) has a depth-gated fog: a rule at line 1920 randomly hides distant cells and shows only wave-noise while you are above 50 feet, so map quality is a function of your depth.

• Convoy (p.38): a 10×10 sub hunt against a computer convoy of one cargo ship and two destroyers. The fixed turn sequence (lines 240-280) is: convoy moves, you move, optional torpedo, periscope search, second move. The cargo ship drifts 0-3 squares per turn toward its goal (line 950). One destroyer is an escort locked within one square of the cargo ship, shadowing it and guarding the approaches; the other is a roaming hunter. Torpedoes fire along eight compass bearings and walk cell-by-cell testing each step for a hit (lines 1500-1520). The periscope routine (from line 1740) scans only the eight neighbours of your square, so contacts are partial and noisy.

• Geowar (p.64): coordinate-geometry artillery by Gary Lorenc (Creative Computing, May/Jun 1975). You sit at the origin and fire an infinite-range straight laser at a chosen bearing of 1-90 degrees, hunting five hidden installations in a 30×30 grid with a cleared zone around your base. All the math runs in angle space: DEF FNV (line 54) converts a slope to a degree via arctangent, each target’s exact bearing is precomputed (line 73), and per-target hit windows and wider scare windows are precomputed as bearings to the target’s ±1 and ±2 lattice offsets (lines 147-151). A shot tests the entered degree against each target’s windows in order (lines 92-98). A near miss scares the target into relocating and cancels non-direct hits earlier on that ray. Because the ray is infinite, one bearing can hit several collinear targets.

• ICBM (p.72): a pursuit/intercept game derived from a program by Chris Falco (Creative Computing, May/Jun 1975). Radar reports an incoming missile; you launch a SAM and steer it by heading only. Your SAM’s speed is randomized at launch and never disclosed (line 130), which is the design’s weak point. Per turn the SAM advances along your heading (line 290) while the ICBM steps toward the origin along its own bearing plus a random deviation that shrinks as it closes (lines 350-380). Intercept is D < 5 miles (lines 390-430). About 2% of turns fire a random accident branch. There is no lead-computing solver: the targeting model is a human closed loop against a jinking, unknown-speed target.

• Grand Prix (p.66): one timed lap of a 3200-yard circuit, four straightaways and four curves. Track geometry is data (segment boundaries at line 9010, curve speed ranges 9020-9050), and the opponent’s position-versus-time comes from an H() lookup table (9070-9130) scaled per opponent. The player acts turn-by-turn, not by authoring a strategy: on every straightaway the game steps time in intervals and prompts for an acceleration value each step, clamped to the chosen car’s max acceleration and braking. Motion is classic kinematics, X1 = X + S*T1 + A/2*T1² and S = S + A*T (lines 3320, 3530). Curves auto-resolve from entry speed against that curve’s safe band (subroutine at line 8000): clean below the limit, then wide, then a spin, then a crash that ends the run.

Mineable patterns

• Deduction from local rules, with no solver. Blackbox computes every ray outcome from three-cell adjacency, one step at a time. Rich emergent puzzle behavior from a purely local rule is cheap to implement and hard to exhaust.
• Discrete, geometry-shaped feedback beats hot-and-cold. Blackbox’s three-way absorb/reflect/deflect signal is shaped by the layout of several hidden objects at once, which rewards logical inference rather than gradient-following. This is a genuinely higher tier of feedback than the first book’s targeting games reach.
• A moving target with a defender. Convoy’s drifting cargo ship plus a shadowing escort turns a static bracketing puzzle into a lead-and-thread problem, without adding a subsystem.
• Hazards that cut both ways. Seabattle’s mines and sea monsters kill the enemy fleet as readily as the player, so the map is an actor rather than scenery.
• Instrument quality as a resource. Seabattle’s sonar fog is gated on your depth, so information is something you pay for with exposure.
• A near miss that changes the problem. Geowar’s scare-and-relocate means a poor shot actively degrades your accumulated knowledge, which punishes spraying far more effectively than simply wasting ammunition.
• Angle-space precomputation. Geowar resolves everything by comparing one entered bearing against precomputed windows, so an apparently geometric problem costs almost nothing per turn.
• One dial with several consequences. Grand Prix’s per-interval acceleration and ICBM’s heading are single inputs that resolve against multiple coupled systems.

KN-86 resonance

Concept-level here; the full per-cart mapping across all 17 cartridges is in ../synthesis-basic-games.md.

• Blackbox is the strongest single find in this volume: an untimed probe-deduction puzzle whose feedback is discrete and geometry-shaped, with a very small implementation surface.
• Convoy and Seabattle bracket the sonar-hunt design space: the tight moving-target hunt at one end, a campaign-scale living map with an arsenal and a resource ledger at the other. Directly relevant to depthcharge.md.
• Seabattle’s depth-gated fog is a ready monochrome mechanic: information quality rendered as dither density, tied to a resource the operator controls.
• Geowar’s bearing windows and scare-relocate are triangulation material, relevant to the signals family rather than to a hunt cart.
• Grand Prix corrects a tempting misreading. It is a manual reaction game, not a program-your-driver game. A KN-86 version that has the operator author a driving policy in the onboard REPL would lean into the deck’s programmable identity, but that is new design rather than a port.

Assigned to carts

Josh’s calls, made in the kn86-inspo workbench. Full map: cart-inspiration-map.md.

Game	Destination
Blackbox (1979)	Shellfire
Convoy (1979)	Pathfinder
Geowar (1979)	ICE Breaker, Sysop Mode
Grand Prix (1979)	Nodespace
ICBM (1979)	NIGHTOWL
Seabattle (1979)	Depthcharge

Sources & verification

• Confidence: HIGH on all mechanics. Every game above was read directly from its printed listing and sample run, not from secondary sources. Line numbers cite that printing.
• Book identity confirmed from the title and copyright pages: Workman Publishing Company, copyright 1979 Creative Computing, first printing June 1980, ISBN 0-89480-137-6, LCCN 80-57619. The cover advertises 84 games.
• Publication-year note. The copyright is 1979 and the first printing is June 1980; this entry uses 1979 as the year, consistent with how the volume is normally cited.
• Blackbox provenance is stated in the book: a computerized version of the game from the August 1977 Games and Puzzles, with a previous version in Creative Computing May/Jun 1978, program and description by Jeff Kenton.
• Grand Prix’s origin is uncertain in the source itself. The book gives “PUC Gran Prix” and Ahl guesses Pacific Union College. Recorded as printed.
• Seabattle’s listing was skimmed rather than fully traced: it is one of the longest in the book. The command dispatch, resource set, terrain codes, enemy movement pass, and depth-gated fog rule were read directly; per-line combat arithmetic was not.
• ICBM’s unknown SAM speed is a real design flaw, not a reading error. The book itself suggests three expansions (operator-set speed, a 3-D altitude angle, all-quadrant approach) that would address it.