Discuss Close the Gates here

[groza528]

Link to puzzle

Maybe this one will last a little longer...

[Sprocket356]

Ok I don't know what this is all about quite yet. I have identified these symbols as part of a "logic gate" or are related to a typical "logic gate", whatever that means. This is also seen the the puzzle title "close the gates" and also in the, puzzle description stating "logic". I wasn't able to find the meaning of the 5 symbols that are found at the top of each logic gate. The U and "upside down U" shapes are mathematical symbols.

I guess I should read up on logic gates to figure out if im supposed to plug in numbers, letters, or whatnot in these diagrams. Wiki Logic Gate for more information.

I notice a lot of alliteration in regards to dan's depository...

I notice 5 logic gates - A,B,C,D,E and I notice 5 seperate lines (paragraphs we shall call them) in the dialogue of the puzzle.

[ralphmerridew]

How about this:

Define set A as the set of all 5 bit numbers that produce a 1 when passed through the first set of gates. Define B,C,D,E similarly.

Calculate the seven sets formed by union / intersect / set-difference on those five sets as described in the numbered lines.

I predict that each of those will produce a set with one number, and that number is between 1 and 26 (or possibly 0 and 25). Converting that to a letter will spell out the final answer.

Now I just need to sit down and do the work.

[Sprocket356]

Ralph.. I think you might be on to something, I have never done one of these, but I am eager to try to figure it out!

[ralphmerridew]

My name is "ralphmerridew", or "rm" if that's too long. It is always lowercase and never abbreviated to "Ralph".

[Sprocket356]

wow we are a bit sensitive RM? I didn't mean to Ralphel your feathers!

Notice in A that only 4 bits are utilized instead of 5. I really don't even know where to start with this thing.

What do you figure the U is for in #7; that's not a listed gate.

[mrsmathteacher]

I can't imagine that we have to input every possibility in every gate as the first step. That would be 160 calculations. There must be a way to narrow down the input.

[Sprocket356]

How would you break down decimal numbers to 5 bit binary?

Do you divide by 2; much like 8 bit but only 5 times?

[mrsmathteacher]

I think of it more as different place values. Fill in how many 16's, 8's, 4's etc.

[Jack_Ian]

Well, I did a little work on Diagram A (about 5 minutes so it's very possible I made a mistake) which might help those not familiar with logic diagrams.
Assuming inputs x0, x1, x2, x3, x4

The diagram can be represented as follows: (x0.((!x1).(!(x2+x4)))) + (x2.((!x1)+x4)
where "." is AND, "+" is OR and "!" is NOT

So...
The statement will be true if (x0.((!x1).(!(x2+x4)))) is true OR (x2.((!x1)+x4) is true
(x0.((!x1).(!(x2+x4)))) is true if x0=1 and x1=0 and x2=0 and x4=0
(x2.((!x1)+x4) is true if x2=1 and (x1=0 OR x4=1)

so, where x can be either 1 or 0, the following will provide a true result:
100x0, x01xx, xx1x1

I don't have time to do the others just now, but it should be simple enough to do if anyone is interested.

[mrsmathteacher]

Okay - I've been crunching numbers, and unless I've made a mistake somewhere I have more than one solution for some of the 7 descriptions.

[referee]

The U in # 7 would be the Universal set, ie the set of all possible combinations.
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[Oscar]

ralphmerridew was close with his suggestion, but the results are not always one number/letter. The whole thing spells something which any self-respecting kid would have made for himself at one time or another, without needing to go to Duplicitous Dan, in my view.

[mrsmathteacher]

So much for this one lasting longer.

[trickster]

I think there is a number letter relationship but in 5-bit code. One I found on internet called Baudot...

[Oscar]

Interesting suggestion, trickster, and by all means pursue it, but the fact that using the mechanism suggested in post #3 results in:
a) 7 sets all with numbers between 1 and 26 which
b) when converted using 1=A, 2=B etc spell out a recognisable phrase
suggests to me that you won't get very far.

[trickster]

About post #3, Oscar, I think that if we have a 5 bit input then we' ll have binary numbers from 00000 to 11111 (decimal 0 to 31) thus 32 combinations...BUT as you, so right predicted it leads me to nothing for four possible reasons: 1.I miscalculated the 7 sets or the output of the 5 set of gates or 2.I can't find the 5bit code that fits to it or 3. though the above two are right it requires one more step or 4.It's all wrong from the very begining...

[zzzp2]

http://www3.wittenberg.edu/bshelburne/Comp150/s_fourga.gif
here's a link showing the different types of logic gates
_________________
new kid

[zzzp2]

for all, you are supposed to put numbers, FYI
also, for A, all ones make 1, and all 0's make 0.[/spoiler]
_________________
new kid

[groza528]

Someone want to go ahead and spoil the final answer? Looks like the method is all there.

[groza528]

...anyone?

[Oscar]

Sorry, groza, I assumed that, given how 'simple' it was, there'd be a rush of spoilers

Spoiler:
Solving for the inputs which gave an output for each grouping of gates, and treating them as 5 binary bits gave these decimal number sets:
A - 4-7,13,15,16,18,20-23,29,31
B - 0,1,8-10,12-14,16-18,20,22,24-26,28,30
C - 0-7,11,14,18,24-31
D - 0,2,5-7,14,15,22,23,30,31
E - 1,3-7,9-15,17,19,21,23

Thus the 7 set manipulations are:
1. 2,15,23
2. 1,14
3. 4
4. 1,18
5. 18
6. 15,23
7. 19
which when translated using a=1, b=2 etc gave the result:
bow and arrows

PS Please excuse any sarcasm, I think it's a well crafted puzzle.