Engineer of the People

In KOHCTPYKTOP: Engineer of the People, you play as an engineer working in a semiconductor factory designing integrated circuits based on specifications provided to you. What does it have to do with communism? You’ll have to play to find out!

A few notes about the game:

  • This game is actually quite difficult; while you don’t need to know anything about electronics to play, being familiar with some of the concepts will definitely help in the later levels, as most of them are based around real-life circuits. Wikipedia is your friend.
  • The music playing is tracks one and five from CŒDES Pierre-Marie’s SYMPHONIE N°2 available on jamendo.com.

Requires: Flash

Play Kohctpyktop: Engineer of the People


  1. minecraft for wii January 24, 2013 9:45 pm

    There is definately a lot to find out about this subject.
    I love all of the points you have made.

  2. Serge SB February 9, 2013 12:45 pm

    Many thanks for the great game! Just one question: could you please make controls more user-friendly and convinient?
    For example (number is the key on keyboard and respective icon to the right):
    1: silicon n
    2: silicon p
    3: metal
    4: via
    5: select
    Holding shift on 1-4 modes deletes respective items.
    Also, 1-3 have checkboxes near them to display/hide these layers.

    And final question: could you please make native clients for windows and/or android?

  3. sulai August 27, 2013 7:34 am

    I really like this game so much. Great Work Zach!

    Many requests for Diodes. Here is one:


  4. sulai August 27, 2013 8:47 am

    I posted a sticky diode. This is a non-sticky diode:


  5. meisl September 9, 2013 8:46 pm

    Absolutely awesome game!

    I just went for minimal solutions. Minimal wrt space and delay. Also, avoid spurious one-cycle spikes, both on power-up and on switching.
    Here’s one for 4-input AND/OR gate:

  6. meisl September 9, 2013 11:38 pm

    Even smaller 4-input AND/OR gate:

  7. meisl September 27, 2013 12:46 am

    Hi there, I’ve completed all the levels now and one thing that I noticed is that the verification isn’t really optimal. For example level 15, the 8 BIT ADDRESSABLE SRAM, can be accomplished by implementing only three instead of all eight SRAM cells.

    I am aware that this is a non-trivial problem and that a brute force approach would be hopeless; at least for circuits as complex as level 15 with a *really* huge state space (you know it, one really has to consider combinations of *edges* in the input signals, not only their levels, which makes for a factor of 2 in the # of boolean variables).
    What I can see in the game is only a fixed and quite limited (ie nowhere near exhaustive) test protocol and some statistics to allow for a bit of fuzzy flexibility with regard to timing. This, as said, is IMHO not nearly enough for circuits as complex as eg the SRAM. As a side-effect this also renders the “DESIGN-score” rather meaningless (see eg the “high-scores” over at http://www.kongregate.com/games/krispykrem/kohctpyktop-engineer-of-the-people).

    So, I just wondered: have you thought about employing TEMPORAL LOGIC, ie model checking? If you have then I’d be interested in your reasons for not including it in the game. What I have in mind is a really precise specification (player not necessarily bothered with, of course) and instead of “not passed” there’d be really constructive critique, that is actual counter examples of input signal sequences. Btw, “precise spec” doesn’t mean that there’d be no flexibility wrt to timing; rather on the contrary: the bounds of an acceptable response signal would be exactly definable.

    In any case I, personally, will explore this further, So I’m wondering if there’s there any chance for cooperation on this. At best you’d put the whole thing on github – but well, I know…


  8. meisl September 29, 2013 8:20 pm

    For everybody else like me who found this truly marvellous gem of game only now (and not when it was “hot”, in 2009):

    http://thesiteformerlyknownas.zachtronicsindustries.com/?p=710 is the old forum for this game, up till Oct 2010 (oh, how I wish I had been there…)

    http://www.nerdparadise.com/tech/electronics/circuits/kohctpyktop is another old forum

    http://www.kongregate.com/games/krispykrem/kohctpyktop-engineer-of-the-people?acomplete=kohctpyp let’s you play it and has a high-score list and also user comments

    To play offline simply download
    http://www.zachtronicsindustries.com/kohctpyktop/kohctpyktop.mp3 [optional]
    Note: you can remove the two <script> … <script> tags from the .htm if you don’t want google-analytics to be informed.

    Well, particularly in the old forum (1st link) there are many complaints/requests about a better verification metric (not only re the SRAM) and also for a “sandbox”, ie. custom test-protocols and/or kind of a level-editor (for creating new design challenges). So I figure I’m not the only one who’d love to see this fantastic thing be continued/improved/extended…

    As said, I’m serious about me putting some effort into improving this wonderful game. Zach, I’d understand if you don’t want to open it up completely, eg. on github. But maybe you could provide some hints regarding the format in which designs are saved? That would be really great :)

  9. meisl September 29, 2013 8:57 pm

    Just one idea for a quite interesting and instructive new challenge would be an “edge detector”: it should give a short, one-tick lo-to-hi pulse on the output whenever the input goes from
    a) lo to hi
    b) hi to lo
    c) either lo to hi or hi to lo
    Each of these should have as minimal a delay as possible, but, particularly wrt c), the delay should be the *same* for either edge.

    a) can be used to turn an S/R Latch into a Toggle Latch.

    One could then combine this and Toggle Latches to accomplish another challenge, an “edge counter”. This would lead to “double-data-rate” techniques where switching occurs at both, the rising and falling edge of the clock signal…

  10. cj October 8, 2013 12:32 pm


  11. meisl October 19, 2013 12:19 pm

    Ingenious creative design, cj. Congratulations!

  12. Johnman October 29, 2013 6:07 pm

    Inspired by meisl’s comments, with which I greatly relate to, I set out on a little experiment.

    I was here when this game came out (as “Sallen”), and have been coming back ever since. There’s something really endearing about it.

    Those interested in taking the concept of this game further should check this out: KNOH Github repository.

  13. meisl October 29, 2013 8:23 pm

    Whee-oooh – that’s so great, Johnman!
    In fact, I had only little hope to find someone here to collaborate with. Even less someone who just puts up repo!
    Unfortunately I’m not so much of a C++ guy … but well, we’ll see.
    cu on github :D
    p.s.: don’t be scared off by my replying so fast, it really is a coincidence that I came back here right now :)

  14. Johnman October 31, 2013 5:31 pm

    Just a heads-up: you can now get a preliminary build of the clone at the Github repository ;)

  15. dnr December 19, 2013 7:03 pm

    This is awesome johnman and meisl! Do you plan to increase the available area? The original one is a bit limiting, would be hard to build something more complex than the last couple of original levels.

  16. RA2lover January 1, 2014 10:35 pm

    There’s a possible bug in which gates don’t let signals go through them to the other side.
    see this kt141ao design: http://imgur.com/Ju0hAUO


  17. Seraku January 2, 2014 7:05 am

    @RA2Lover: I, for one, leverage these so-called “double-sided gates” when completing some of the later levels that require designs to be very minimal. The fact that the signal does not propagate across the gate helps you avoid a signal polluting the rest of your design. It helps to imagine that the game treats a double-sided gate as two gates in parallel:


  18. Christopher January 17, 2014 5:04 pm

    I have been having trouble with every SR latch designs. They all seem to bounce back and forth until the first set any idea why this happens? Here is my latest design.


  19. Xiver January 26, 2014 5:10 pm

    I would definitely purchase an android copy of this.

  20. prospero.78.su March 21, 2014 8:35 pm

    Я может совсем тупой, ну правда не понимаю, как нарисовать моновибратор?….

5 Trackbacks

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  5. By Zach Barth on Spacechem on May 29, 2012 at 2:33 pm

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