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# 2025-08-08 - Robot Odyssey, Escape From Robotropolis
My high school German class used learning software in the obsolete
Apple II lab. Normally i finished my work early and had time on my
hands. I explored boxes of old software on the counter, and i fondly
recall playing Robot Odyssey, a puzzle game. I played it on a green
CRT.
(TXT) Robot Odyssey (Wikipedia)
Recently i found appler, an Apple II emulator for the IBM PC and
decided to give it a spin. It compares favorably to the other MS-DOS
Apple II emulation software (appleuni, capple, applepc, sim2e, and
xgs) on ftp.apple.asimov.net.
(DIR) Appler - Apple II emulator for MS-DOS with TASM source code
Note that appler was once a 16-bit application but now it requires a
32-bit processor.
(DIR) ftp.apple.asimov.net
I went ahead and packaged Robot Odyssey with appler and tested it in
DOSBox and in SvarDOS on real hardware. It is more colorful than the
IBM PC port and it works great!
(DIR) Robot Odyssey in Appler (ro-apple.zip)
Alan Kay said it would be impossible to create this game on early
1980's hardware. Never tell a hacker that something is impossible!
The game is "way out there" because you can design chips in game.
The novelization of this game contains prescient social commentary.
See articles below for more details.
# 2025-Apr-10 - A Robot Odyssey Odyssey by Sean Duggan
Decades ago, I experienced Robot Odyssey on my family's TRS-80 Color
Computer, and it was awesome. The basic concept of the game was that
your character is preparing for bed when they fall through the floor
of their room into the underground city of Robotropolis, where they
have to program three robots to find their way home.
(IMG) Opening Animation
## The Game
And how do you program them? Was it BASIC? C++? Python? Some bespoke
scripting language? Nope, you program them with logic gates. Every
robot came with four bumpers and four thrusters, corresponding to the
four cardinal directions, as well as a grabber and an antenna which
come with an input and an output. You wire them together with OR
gates, AND gates, XOR gates, and FlipFlop circuits (and nodes, but
they're essentially a convenience to split the signal). And, with
those, you solve everything from simple puzzles involving going right
until you hit a wall, and then going back again, to navigating a
minefield by communicating via the antenna (which is entirely binary,
so you have to figure out how to communicate via that!), to hitting a
series of 8 switches in a very specific order within a short amount
of time. The first level could be completed with the robots as wired,
just putting them in place and watching them run. The second level
required fairly basic logic, around the level you'd probably
understand in grade school. Third level and above... you're starting
to get into concepts that are so complicated that you're getting into
undergraduate levels of problem-solving, requiring you to get the
robots to count, to store and retrieve data, to navigate mazes... and
all of this with logic gates.
Honestly, one starts to understand why, despite the game technically
being titled Robot Odyssey Part 1: Escape from Robotropolis, we never
got a Part 2. As a child, I made it to the third level, and my older
brother who went into software engineering made it past the fourth
level, but frankly, the late levels were getting into college-level
thinking and beyond, with them dumbing down later games that used the
engine, like Gertrude's Secrets. But still, making my way through the
game as a child was, I think, one of the reasons I became a software
engineer myself. It requires a degree of creativity and logical
thinking that I think too few children are pushed toward these days.
Which leads me into the reason I wrote this article.
## The Book
Yes, the game got a novelization, Robot Odyssey I:
Escape from Robotropolis and, much like the game it was based off of,
it looks like a book for children, but is really written to a much
higher level.
(IMG) Book Cover
The basic plot is simple. Homer is a child in a future where robots
are a routine part of life. One of his childhood toys is a robot
named Denby, that he considers to be his friend, up until it goes
missing. He meets a bright boy his age named Les, and they follow a
shared vision, to create a new Denby, made in human form, and as
intelligent as they can make him. Hiding their activities from their
parents, they learn enough to put him together and activate him...
only for tragedy to strike. Upon activating Denby, a shock knocks
Homer unconscious and when he awakens four days later, he's told that
Les was killed by the shock, and Denby had melted down. Homer, of
course, is despondent, and further finds that himself discontent with
current society, where robots are taking over every aspect of human
existence, and children are growing increasingly ignorant as they
stop learning things that robots can do for them.
> But what was it that people did best?
>
> No one was quite sure. Some people argued that humans were more
> creative than machines, so they should let machines do the
> "donkey thinking" and concentrate instead on creative
> thinking--things like making music and sculpting statues. Other
> people said that since work was being automated anyway, people
> would soon have more leisure time. Instead of thinking about work
> they should be thinking about having fun. "Having fun can be a
> uniquely creative, uniquely human, activity," said one expert,
> quoted in Technology Times magazine.
>
> Teachers eventually bowed under all this pressure, and machines
> took over the classroom, just as they had taken over offices,
> homes, and factories. Teachers rationalized this takeover by
> telling each other that they would let the machines do only the
> low-level mechanical work like looking up names of presidents, or
> solving algebra problems, or conducting a chemistry experiment.
> This would enable them to teach students the higher-level,
> conceptual subjects that human minds were supposed to be good for.
>
> But they didn't.
>
> That's because most teachers were not prepared to teach
> higher-level thinking skills to their students. They hadn't learned
> them when they were in school, and they didn't have the time to
> learn them now. Besides, for the first time in years, they were
> getting a break. Smart desks, intelligent tools, and
> teaching-assistant robots were doing most of the teaching, grading,
> and record-keeping. Kids' test scores were soaring (since the
> machines helped them answer most of the questions). So why put the
> extra effort in just to teach abstract concepts?
Ouch... that kind of sums up what so many experts are saying is
happening to the current generation of kids, not to mention the dire
warnings of what will happen when the expert systems start breaking
down, because the generation that would have learned how to fix them
by doing the little things won't exist, because the expert systems
have been doing those little things. Homer's odyssey (Oh... I see
what they did there) also touches on the dangers of ubiquitous
surveillance and the dissatisfaction when your job comes down to
plugging the diagnostic computer into a system and following its
instructions, leading to Homer using drugs (well, neurostimulation)
and escapist games of sex and violence to escape this soul-sucking
existence. Really... this book was terribly prescient.
## Robotropolis
You might ask what this has to do with the game now... well, halfway
into the book, the robots abduct Homer to Robotropolis, and explain
that he is a danger to their plan of world domination because he has
the temerity to think for himself, rather than to follow the
instruction of the robots. Oh, and robots are actually the minions of
ancient aliens who want to avoid humanity from growing too strong and
challenging them, with them having put a lot of effort into getting
humanity to fear constructing machine intelligence in their own image
and thereby realizing their own greatness. Yup, tales of Prometheus,
Talos, the Prague Golem, Frankenstein, and R.U.R. are all the results
of robots trying to discourage human creativity. They don't quite
understand how an aberration like Homer came about, so they're
testing him by tasking him to escape Robotropolis within 24 hours
while they monitor him so that they can understand where their
protocols went wrong. And thus, the narrative speed-runs the game.
It's actually pretty amazing just how true to the game the book is...
I recognized level after level despite that they inject actual plot
into bits that were frankly probably just decoration, like the
disassembled bots on one level (noted to be torture of robots who
rebelled against the central order) or aliens on another. Homer
experiences genuine peril and distress as he escapes death by the
skin of his teeth, and even wrestles with the Teletransportation
Paradox (sometimes discussed as the Transporter Problem) when he not
only realizes that taking the teleportation device between levels is
technically dying and having a new him created at the other side, but
also starts to realize from some comments by his Mission Control (a
voice contacts him early on, and cryptically explains aspects of the
world, and how to solve puzzles) that he has probably died on parts
of the level, only for the transporter to spit out a new copy of him
who is then better informed of the perils before him. There are bits
of the levels where puzzles are mixed up, but many of them are
extremely recognizable, to the point where the novel could act as a
hint book to the game.
I will admit that I was expecting a slightly different twist than the
one that the book ends on, but suffice to say that not all of what
happened in Homer's childhood is exactly as he remembered it, and
there's a reason behind his being tested like this. It's not much of
a spoiler that he escapes Robotropolis, and vows to come back and
free the enslaved in the underground city in Robot Odyssey II, were
the sequel game and book ever written. At the end of the book,
there's hope for humanity, but I can't help but feel that Homer has
quite the trek still ahead of him. And maybe, just maybe, we can
learn a bit from how dismal his future was, and how we can fix that
in our society today.
## Start Escaping Robotropolis Now
You've made it this far into the article? Congratulations! You've
earned the earned the right to challenge Robotropolis yourself!
There's an online copy of the game. Or, if you want an expanded
experience of the game (and the chance to expand it yourself), Thomas
Foote wrote a Java implementation of the original game (complete with
a super-secret sixth level with even harder puzzles, as well as
improvements in the interface and the Innovation Lab!).
(HTM) Robot Odyssey Rewired
(DIR) DroidQuest
Explore! Learn something new! Share the frustration of incredibly
difficult puzzles in a game marked as 10 and up!
And, above all, never stop thinking and creating...
(IMG) Splash Screen
(HTM) From: https://medium.com/@sean.duggan/a-robot-odyssey-odyssey-34707092639d
# Other Chips In Robot Odyssey
## Stereo Recorder chip
Here's the schematics of the Stereo Recorder:
(IMG) Stereo Recorder schematics
Each nested chip is a Mono Recorder. Here's how a Mono Recorder is
done:
(IMG) Nested chip: Mono Recorder - schematics
It's actually a circle of OR gates. The "recording" is stored in the
intermediate subnets.
Note that the above version is not binary-compatible with the
original Stereo Recorder, that is, it does not produce the same
savefile. The following version is binary-compatible, but it's a bit
uglier:
(IMG) Nested Mono Recorder, binary-compatible
The total chip length is 516 bytes, which exceeds two sectors by just
4 bytes. It's possible to reduce the length up to a point where four
chips fit, more than doubling the total tape length.
The idea behind this is to use inverters instead of OR gates. The
following section shows a design.
## Enhanced Stereo Recorder
Here's a design using the above idea to build a 72-clock stereo
recorder chip. It uses this nested chip as "tape":
(IMG) Delay line made of 35 inverters in one chip
That chip uses 190 bytes The master chip uses 4 instances of it:
(IMG) 72-clock stereo recorder diagram
The total size is 852 bytes, so there's still room for some more
inverters in case a recording of more than 72 clocks is needed
(remember the maximum is 1024 bytes). A mono recorder of about 150
clocks would also be possible.
When I was checking the design I noticed an anomaly which seems to be
a bug. I don't know if that bug was removed in v1.1. It's in the
input of one of the inverters in the nested chip:
(IMG) Possible bug in RO
It would probably be possible to make a "quad recorder", though the
controlling logic would also take space. The idea is to have four
pins for output, a recording input, an erase input and two "tape
select" inputs that would make the recording and erasing pins act on
the desired tape. I estimate that it can be done using eight extra
ANDs and four inverters.
## Count to N chip
This is a TkGate diagram of the chip. It's somewhat complex. It has
five nested chips, three of one kind and two of another. Both nested
chip types are the same thing except for the pin layout, probably to
avoid too many crossings. I've titled them LNC (Left Nested Chip) and
RNC (Right Nested Chip).
(IMG) Count-to-N chip diagram
The LNC:
(IMG) Count-to-N chip diagram, LNC
The RNC:
(IMG) Count-to-N chip diagram, RNC
This time I didn't take the effort to draw the junctions in RO-style.
I have placed buffers because TkGate doesn't allow me to interconnect
two module outputs. For the simulation I used the same flip-flop as
in the Wall Hugger. In order for the simulation to work properly, I
needed to adjust the inverter to a custom delay of 8 cycles.
Every nested chip is a bit in the chain. Let's examine just the LNC,
as the RNC is the same with some pins different. But first, note that
the inverter plus the AND gate make a raising edge detector that
throws a 1-clock pulse every time the count pin is active.
Pin 7 is obviously the reset pin. When it is activated, the flipflop
is reset.
Pin 6 is the Pulse input.
Pin 8 is the Previous Output input pin. When it is 1, it means that
the previous output is set, so we're next. When that happens, the AND
gate gives permission to the counting pulse to pass through and set
the flipflop.
When the flipflop is set, it must be reset at the next counting
pulse, so the output is fed back to the Reset input through an AND
gate with the counting pulse.
Pin 5 is the Next Output pin for chaining. Pin 2 is for connecting to
the main chip's pin.
Now for the main chip circuit. There are five chips to feed five
outputs, plus two extra flip flops. The lower one in the diagram is
initialized to 1 on reset, because it acts as the "previous output"
for the first nested chip, so that it knows it's its turn. It is
reset by the output of that first nested chip.
The upper flipflop is the last bit in the chain. That bit has a
special treatment because it must not be reset on the next pulse,
only on global reset.
(HTM) From: https://web.archive.org/web/20180131084757/http://www.formauri.es/personal/pgimeno/temp/RO/stereorecorder.php
# 2014-01-24 - The Hardest Computer Game of All Time by David Auerbach
It was called Robot Odyssey, it took me 13 years to finish it, and it
sealed my fate as a programmer.
My first computer was an Apple IIe with 128KB of RAM, no hard drive,
and a 5-1/4" floppy drive. One of the top educational games back then
was Rocky's Boots, an inventive game that taught the basics of formal
logic to kids. I loved it when I was 6. Two years later, I got Robot
Odyssey, which promised to expand on Rocky's Boots by extending the
formal logic to actual programming. The game devastated me. My brain
could not comprehend how to solve its puzzles. I finally finished
it--13 years later, and not without some assistance.
Let me say: Any kid who completes this game while still a kid (I know
only one, who also is one of the smartest programmers I've ever met)
is guaranteed a career as a software engineer. Hell, any adult who
can complete this game should go into engineering. Robot Odyssey is
the hardest damn "educational" game ever made. It is also a stunning
technical achievement, and one of the most innovative games of the
Apple IIe era.
Visionary, absurdly difficult games such as this gain cult
followings. It is the game I remember most from my childhood. It is
the game I love (and despise) the most, because it was the hardest,
the most complex, the most challenging. The world it presented was
like being exposed to Plato's forms, a secret, nonphysical realm of
pure ideas and logic. The challenge of the game--and it was one
serious challenge--was to understand that other world. Programmer
Thomas Foote had just started college when he picked up the game: "I
swore to myself," he told me, "that as God is my witness, I would
finish this game before I finished college. I managed to do it, but
just barely."
(IMG) Programming in your pajamas: the simulation by Gil Morales
In Robot Odyssey, you played a character who falls in a dream into
the mysterious city of Robotropolis. There were five ascending levels
to Robotropolis before you could return back home. Here's a rough
estimate of their difficulty:
Level Difficulty
------------------------- --------------
The Sewer Moderate
The Subway Challenging
The Town Very Difficult
The Master Control Center Impossible
The Skyways Impossible
(IMG) Robotropolis as rendered by Gil Morales
By my teenage years I'd completed the first three levels, but my
siblings and I hit a brick wall with the fourth level, which is to
earlier levels like algebra is to arithmetic. (As Thomas Foote said,
"I was stuck on this level for most of my college years.") The fifth
level was nothing more than a fabled dream. The Internet didn't exist
in those days, and even finding someone else who had played the game
was difficult if you didn't live in Silicon Valley.
The game became my bête noire, a lingering reminder of my inadequacy.
To give you some idea, I couldn't get past the fourth level even
after I'd been programming in BASIC and Pascal for years.
The game had a profound effect on those who played it. My younger
brother, who suffered with my sister and me as we struggled through
the game, told me, "It's where I started on the road to becoming a
programmer." Even if players got stuck (and everyone got stuck), the
game offered ideas and concepts that no other game did. Game designer
and hardware hacker Quinn Dunki of One Girl, One Laptop wrote Gate, a
spiritual successor to Robot Odyssey that employed many of the same
concepts. The tech law professor James Grimmelmann told me it had
been his "game for a rainy decade," describing an immense sense of
accomplishment on finishing one of the nastier puzzles--"a big part
of why I loved programming." Programmer/musician/hacker Joan Touzet
used it to teach programming to middle schoolers--in 2004. Thomas
Foote was so taken with the game that he spent years re-implementing
the entire game in Java, with the support of a small but dedicated
fan community. (One of them remembers completing the game and getting
a certificate from the Learning Company declaring him the 34th person
to finish.) Foote called his version DroidQuest, and it is the
easiest way to play Robot Odyssey today.
(HTM) Gate by Quinn Dunki
It's an accomplishment.
Software engineer Micah Elizabeth Scott, who ported the game to the
Nintendo DS, told me that Robot Odyssey "played a large role in
shaping who I'd later become," and emphasized just how personal and
distinctive a creation it was: "You see the style of an individual or
a very small team, uncluttered by corporate structure or modern
abstractions."
It's a testament to the sheer free-spiritedness of the early days of
consumer software that such a game could even get made. The Learning
Company, who also made classics like Rocky's Boots, Reader Rabbit,
and Gertrude's Puzzles, was a small company founded in 1980 on an NSF
grant by three educators who had taken an interest in software:
Leslie Grimm, Ann McCormick, and Teri Perl, as well as Warren
Robinett (who had created the world's first Easter egg when he hid
his name in a secret room in Atari's Adventure).* The company was
atypical both in focusing on educational software and in being led by
women. Grimm and Robinett designed 1982's Rocky's Boots, which taught
Boolean logic gates to kids, and which had captivated my 6-year-old
self. Grimm also co-authored Robot Odyssey, which began as the
brainchild of Michael Wallace, a 22-year-old Stanford undergrad at
the time.
(IMG) The game taunts you
Wallace told me that writing the game was one of the best times of
his life. Originally a customer service rep at the Learning Company,
Wallace taught himself to code in Apple 6502 assembly by looking at
Robinett's code for Rocky's Boots. After Robinett left the company,
Wallace expanded Robinett's code to architect the underlying
technology for Robot Odyssey, including the dazzling ability to embed
circuits within circuits. Doing this was no easy task; Wallace called
it "an art form" and recounted working 100 hours a week. When Teri
Perl described the project to legendary computer scientist Alan Kay,
he said, "You're wasting your time. It can't be done." That is, the
basic idea was simply too complex to run on an Apple home computer.
When Robot Odyssey shipped, the company gave Wallace a plaque that
said, "It can't be done. --Alan Kay."
After getting her Ph.D. in biology from Stanford, Leslie Grimm became
fascinated by computers and their educational potential while
volunteering in her daughter's school. In addition to directing the
entire project, Grimm was in charge of the game portion of Robot
Odyssey: the five levels of Robotropolis and three tutorials
(expanded to five tutorials in Version 1.1, in the hopes of making
the game a bit more tractable to players). Each of the five game
levels was the personal creation of a single person. I'd like to
single out Shaun Gordon, the 16-year-old high school whiz who
designed the diabolical fourth level, the Master Control Center,
which was the Waterloo for many a player (including myself).
Wallace was kept so busy with the plumbing of the game that he
himself never played it through to completion. I asked him if he
might try someday, and he said, "It might take a year of my life." He
wasn't sure that anyone at the Learning Company had solved the entire
game singlehandedly!
To solve the puzzles, you are given three (eventually four) robot
pals to wire and program. From left to right, they are Sparky,
Scanner, and Checkers. They can move, detect walls, pick up and drop
things, and communicate to one another.
(IMG) Sparky, Scanner, and Checkers: they are yours to command...
When I say program, I mean something a bit more primitive than
computer code, even the low-level assembly that processing chips
natively run. I mean the actual logic gates (AND, OR, NOT) that make
up the innards of chips. So Robot Odyssey was programming, but it was
also electrical engineering. Your tools for implementing "programs"
were the most primitive available. You had "electricity" going
through wires into gates. The gates implemented the primitive
operations of formal Boolean logic.
(IMG) Diagram
Boolean logic is fairly simple. It deals in two opposing values,
often called TRUE and FALSE (if logic is being applied to
assertions), but since we're talking about electricity here, they're
better called ON and OFF. The robots in the game have thrusters that
make them move. For example, if you feed electricity into a robot's
thruster through a wire that is ON, the thruster turns ON and the
robot moves. [1] In addition, there are assorted logic gates that
change the nature of the electricity. A NOT gate had one wire going
in and one wire coming out, and inverted the input wire. If the
incoming wire was ON and had electricity going through it, the gate
would not output electricity. If the incoming wire was OFF, the gate
would output electricity. [2]
(IMG) A "wall hugger" robot. The actual logic is [in] the blue "2" chip.
Using these gates and a few others, you had to wire up robots to
perform tasks--reasonably simple ones at first, [3] but which became
increasingly complicated as the game progressed.
(IMG) Eric Welsh's circuit that "plays" a 100110 pattern on the antenna.
When the task is to get one robot to communicate orders to move to
another robot through an antenna that can only be ON or OFF, those
logic gates start to seem awfully limited in their capabilities. The
trick is, they aren't limited--in sufficient combination, those
little logic gates can do anything. But it takes some real thought.
Getting these simple gates to execute complex programs melted my
brain. My child's mind was literally incapable of making the jump
from those simple gates to the complex control structures required to
solve the game's puzzles. The game offered you the ability to "burn"
circuits into chips in order to abstract control structures. Here's a
chip that uses a lot of OR gates in order to... well, I won't get
into it...
(IMG) Inside a chip: Fun for the whole family!
The point being that those simple logic gates could, in sufficient
combination and organization, do tremendously complicated things.
That, after all, is the very stuff of computer programming, using
primitive operations in immensely complex architectures. For Foote,
the fundamental appeal of the game is much the same as the
fundamental appeal of mathematics and computer science: "The world is
logical, and operates under simple rules. From such simplicity can
come great complexity."
Though a planned sequel (the original box billed the game as Robot
Odyssey I) never materialized, the game won awards and a write-up in
Scientific American. The game got Wallace an audience with the top
brass at Apple and a presentation at Xerox PARC, and he went on to
design electronic toys including the Nintendo Power Glove and now has
his own company, Pure Imagination. Grimm stayed with the Learning
Company and authored many more games, including the successful Reader
Rabbit franchise, and more recently developed educational software
for deaf children.
The sheer complexity of Robot Odyssey made it the spiritual forebear
to today's sandbox games like Minecraft. It probably turned hundreds
of people into computer programmers, and in the hopes of making a few
more, I issue the Bitwise Robot Odyssey Challenge: The first reader
to complete Robot Odyssey--send a save game file to me as proof--
gets a replica of the Robot Odyssey completion certificate from the
Learning Company. Only first-time players allowed--and no cheating by
looking up the solutions!
Notes:
[1]
If you stop the electricity flowing through the wire, the thruster
turns OFF and the robot stops moving.
[2]
An AND gate takes two inputs and outputs electricity if its two
inputs are both on. An OR gate outputs electricity if either or both
of its two inputs are on. An XOR gate (for exclusive-or) outputs
electricity if either of its two inputs are on, but not both.
[3]
Here's a simple example. Let's say you want a robot to move up when
its antenna is receiving a signal (when the antenna is ON), and move
down when the antenna is not receiving a signal (when the antenna is
OFF). You wire up the antenna output to the UP thruster so that when
the antenna is ON, the UP thruster turns on, and vice versa. You also
wire up the antenna output to the DOWN thruster, but put it through a
NOT gate first, which reverses the antenna output. So when the
antenna is ON, the DOWN thruster is OFF, and vice versa.
(HTM) From: https://web.archive.org/web/20190414172920/https://slate.com/technology/2014/01/robot-odyssey-the-hardest-computer-game-of-all-time.html
tags: retrocomputing
# Tags
(DIR) retrocomputing