# I need help with this IQ test puzzle I found online

This puzzle is part of the Monthly Topic Challenge #2: IQ Puzzle Parody

What's missing?

Hint 1 (for use after the first step):

There are three “types” of pixels. You should work through these three sets more or less linearly in some order.

Hint 2 (for use after the second step):

Hint 3 (for use after the third step):

And?

• Do I get any points for "the four choices to pick between are missing"? Aug 5 at 1:37
• What's missing? One white square per grid, why?
– Exal
Aug 5 at 7:03
• I'm willing to give a slight push in the right direction, but I'm not sure if I should at this point, or generally what progress people have, and I don't want to repeat something people already know... Aug 5 at 16:11

## Second Step

Following the clue from Auribouros's answer, if you take…

…every other pixel—that is, the pixels highlighted in red below:

…and then…

…brighten the image, or equivalently color white all pixels that are not pure black…

…you will get:

## Third Step

Combining the clues from the first two steps, take…

…the “white” pixels…

…and look at their…

…pixel values.

For example,

…the first grid has red values:

251 254 251 251 251
254 251   2 255 251
251 254 251 251 251
253 253 251 251 251
251 253 255 251 251

Now subtract…

…the larger values from 255. In the above example this yields:

4 1 4 4 4
1 4 2 0 4
4 1 4 4 4
2 2 4 4 4
4 2 0 4 4

Finally, remove the…

…cells equal to 4, e.g.:

. 1 . . .
1 . 2 0 .
. 1 . . .
2 2 . . .
. 2 0 . .

Which yields a…

Slitherlink puzzle with a unique solution:
(Image from https://www.dougandjean.com/slither/, which I used to solve all of the Slitherlinks in this puzzle.)

We do this once for each grid…

…and each color channel,

…filling in the…

…loop of the solution with pixels corresponding to the color channel, and leaving the rest of the grid black,

…which yields:

(Click on the above or any of the following pictures to see their individual color channels.)

This is where I'm stuck. I tried…

…inserting the pixels back into the original grid (with the color values multiplied by 255 so that the colors of the "black" pixels are visible):

…but it doesn't make any more sense to me. I even tried…

Removing the pixels we used in step 2:

…but that didn't help.

• Great find, good luck on the rest of the puzzle! Aug 6 at 3:06
• @SeptaCube Sadly I don't know enough about [spoiler] to decipher the rest. Aug 6 at 3:15
• Nice job! Any idea what that last symbol is? A colon? An equals sign?
– JLee
Aug 6 at 10:18
• @JLee Just random bits of the question mark I think. Aug 6 at 14:39
• Amazing job on step 3! I will say that rot13 (lbh'er tbvat gb jnag gb ybbx zber ng gur ybbc qenja guna gur pbagnvarq ertvba.) Aug 8 at 0:47

Potentially partial answer, but I think you're missing

this symbol

How do:

The removed squares correspond to numbers between 1 and 25, taking every number and converting it using A1Z26, we get the text HEXCOLOR, which might be missing an S at the end (square in the spoiler above)

• Great start! That isn't the answer though, just a cluephrase :) Aug 4 at 14:29
• Back to the drawing board it is then! Aug 4 at 14:32
• rot13(v qb abg unir gur raretl gb qrpvcure guvf ceboyrz va vgf ragvergl, ohg gur vzntr vf pbzcbfrq bs znal funqrf bs oynpx naq juvgr, jubfr urk pbqrf qvssre bayl znetvanyyl sebz rnpu bgure. tvira gur uvag vg vf yvxryl gung gur fbyhgvba yvrf va gung qverpgvba, ohg gurer ner fb znal qvssrerag urk pbqrf v nz abg tbvat gb grqvbhfyl cber guebhtu rnpu, yby.) Aug 5 at 0:54

Following @Auribouros's partial answer, I took a look at each of the white squares.

I found cough 'several' cough pixel colors (I color coded them to make it easier to put in my revised image):

By the way, I got pretty desperate for colors at the end there. See Wikipedia's List of Colors in case you're confused about 'what the **** is cerise?'

Red: RGB(249, 246, 247), Hex f9f6f7
Green: RGB(255, 254, 251), Hex fffefb
Blue: RGB(251, 251, 251), Hex fbfbfb
Yellow: RGB(251, 254, 254), Hex fbfefe
Magenta: RGB(251, 253, 251), Hex fbfdfb
Cyan: RGB(251, 251, 253), Hex fbfbfd
Light-Gray: RGB(251, 255, 255), Hex fbffff
Dark-Gray: RGB(254, 251, 254), Hex fefbfe
Orange: RGB(251, 255, 251), Hex fbfffb
Brown: RGB(251, 253, 253), Hex fbfdfd
Light-Red: RGB(251, 251, 254), Hex fbfbfe
Light-Green: RGB(255, 251, 251), Hex fffbfb
Light-Blue: RGB(254, 252, 251), Hex fefcfb
Light-Yellow: RGB(251, 251, 252), Hex fbfbfc
Light-Magenta: RGB(251, 252, 252), Hex fbfcfc
Light-Cyan: RGB(252, 252, 251), Hex fcfcfb
Purple: RGB(251, 254, 251), Hex fbfefb
Beige: RGB(254, 251, 251), Hex fefbfb
Chartreuse: RGB(255, 251, 254), Hex fffbfe
Electric-blue: RGB(251, 251, 255), Hex fbfbff
Mauve: RGB(254, 251, 253), Hex fefbfd
Dark-red: RGB(251, 252, 253), Hex fbfcfd
Dark-green: RGB(251, 253, 254), Hex fbfdfe
Dark-blue: RGB(255, 252, 251), Hex fffcfb
Dark-yellow: RGB(254, 254, 254), Hex fefefe
Dark-magenta: RGB(253, 251, 251), Hex fdfbfb (separate from purple; slightly lighter)
Dark-cyan: RGB(255, 253, 251), Hex fffdfb
Pear: RGB(254, 251, 255), Hex fefbff
Orange-red: RGB(253, 253, 254), Hex fdfdfe
Silver: RGB(253, 251, 253), Hex fdfbfd
Desert sand: RGB(251, 252, 251), Hex fbfcfb
Cerise: RGB(253, 253, 251), Hex fdfdfb

So far I haven't finished coloring everything, but I have got this, which I plan to expand in the future: