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Some Good Points

Week 35

You are working for your nation's intelligence agency and notice chatrooms containing random looking images such as this:

After a lot of investigation, a colleague has figured out that if starting at the correct pixel, you are able to obtain a set of valid pixels that will reveal a pattern

More specifically:

• Choose the correct starting point
• 1 of the rgb colour components will be 0 - the other two will be non-zero. The first non-zero value corresponds to the next pixel's x value, the second non-value corresponds to the next pixel's y-value
• Visit the next pixel, determine the pixel that points to (by the 2 non-zero rgb values), visit it and so on...until you encounter a fully black (0, 0, 0) pixel, at which point you have found all valid pixels

If you then display only those pixels in the valid set, you should reveal an image - for example, this primitive smiley can be obtained from the example above

If we walk through the example above, with trial and error, we found the starting pixel to be x=28, y=22, then:

The format for the data below is: Pixel num in set : current pixel's x (column) & y (row) co-ordinate (current pixel's RGB values) 0: 28, 22 (10,66,0) - we start at x=28, y = 22 - this pixel then points to x=10, y=66 1: 10, 66 (0,63,75) - we visit x=10, y=66 and find this pixel points to x=63, y=75 2: 63, 75 (0,68,19) - we visit x=63, y=75 and find this pixel points to x=68, y=19 3: 68, 19 (0,86,75) - we visit x=68, y=19 and find this pixel points to x=86, y=75 4: 86, 75 (65,19,0) - we visit x=86, y=75 and find this pixel points to x=65, y=19 ... ... 19: 75, 75 (10,0,55) 20: 10, 55 (0, 0, 0) - this is black, so is the last pixel in our set

Currently, your colleague's haven't figured out a good way of determining the starting point of the image - though they assume there must at least one way of determining this with just the image file itself, since there are many people in the chatroom and it would be impractical for those sending these images to manually tell others the starting point for each image or brute force every possible pixel as a starting point - perhaps you can figure it out, or wait for a challenge hint

The image you want to decode is below - make sure to right click and download the full resolution image:

For your answer, you should write what is in the decoded image - it will be a famous logo/symbol/organisation (etc) that everyone should be able to recognise. For example, with the smiley image above, writing an answer like "smile", "smiley", "face" etc would all be accepted - if the answer was the Nike tick logo, any answer containing "nike" would be accepted

Submit Answer

Hints

Hints will be released at the start of each of the following days - e.g. the start of day 3 is 48 hours after the challenge starts

Release Day	Hint
2	There is more to an image file - or most file types for that matter - than just the payload data (i.e. pixel values for an image)
3	If you have any command line tools to decode and view image headers like Imagick or ExifTool, you can use that - otherwise searching "view image exif data online" will yield many websites where you are able to upload images and see their decoded headers. Your programming language might also contain built-in image libraries that can parse image headers, which would be ideal, since you wouldn't have to manually check/enter the starting point for each new image
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