So why this #introdcution ?

Well, if you go to a #jobinterview and don't have much experience to brag about.

Take your "private" project and describe what and why you did. (As I did with this introduction)

It helps us (the #interviewers) with:
- understanding how you communicate problems / solutions (#communication , #CommunicationSkills)
- understanding how do you deal with challenges while #solvingproblems
- understand or at least narrow down the level of your #technological #expertise
- just to name few aspects...

Of course it all depends on the kind of job you are applying for.

The interview from my first post was something in between:

#cybersecurity
#penetrationtesting
#redteam

It is very common mistake, that for #cybersec jobs you have to have like 100 0days on your CV, submitting like 1000 CVEs on average in a year and be top 1% on hackerone.

This might be true if you are working alone or certain kinds of three letter agencies but in the average company it is not the case.

You can not and you will not know everything by yourself! You will have to depend on your #team therefore #teamwork and the ability to describe, communicate and solve problems also the ability to deal with unknowns are most important.

#wouldyouliketoknowmore ?

Not all edges looked so nice.
Since I haven't optimized anything I had to work with large error margins.

To make it clear - I use the word "edge" for both cases:
- the while piece edge (contour)
- one side of a piece

therefor I have 1000 contours described with something like 300-600 points per side.

So what about the #complexitytheory ?

Well I had to optimize for space on my working bench. I had about 1m^2 of space and had to move it away if the space was needed for other stuff.

This included:

- dividing whole puzzle into four quadrants (Q1-Q4 in the picture from last post)
- stacking those parts on a hard paper
- creating buckets with puzzle pieces stored in ranges (like 1-50, 51-100 in boxes)
- while working on the quadrant you set focus for the tool which chooses the proper solving direction
- the tool gives you a candidate
- you go to the box
- find the piece (which was very tedious job)
- compare the proposed edges
- mark result (yes/no/next)
- repeat

This all involved a lot of stack and heap work ;-)

So from this point I had 1000 edges stored, I knew where the corners ware. And what now?

Assuming the worst case, where I had to compare all edges. I decided that I wanted to do it only once for each edge pair.

Therefore the main goal of my second #python tool was to compare the edges and hint me with the next probable piece I should try.

Of course I had to go few times back and forth just because I clicked on the wrong button or something.

After many failed attempts to scan or take pictures of the puzzle pieces. I have decided to flip those pieces and work with the grey / blueish background.

I have setup a 30€ webcam placed on IKEA drinking glass pointing down (about 14cm from the lens to the table).

Wrote small #python tool using #opencv ( https://docs.opencv.org/4.x/index.html ) to build an inventory of numbered puzzle pieces. I have stored only the points describing the edges (not the pictures).

So it took me like 3 hours to ingest all 1000 pieces.

I did it once and worked with imperfect data (no optimization, no light adjustment nor camera calibration https://docs.opencv.org/4.x/dc/dbb/tutorial_py_calibration.html ).

I took it as it was, cause nothing is perfect in life ;-)

A thread #introduction :

Recently a candidate in the job interview for my team asked me "what am I doing in my spare time?"

Answer:

If I have enough time I experiment with different stuff (mostly related to computers).

Here one example on solving a #puzzle . Where I had to learn about #computervision , #edgedetection , #complexitytheory (time vs space, wait for it).

The puzzle was given to me as a challenge. "Hey thorkill, you like hard problems to solve..."

It took me over a year to get to solve this puzzle. Thanks to the lockouts caused by COVID-19 outbreak I had time to give it a try. So it all started with this post:

For the sake of #diversity here some random sample for the #followfriday :

3 #ct3003
5 #burnout
5 #followhashtags
5 #macrophotography
5 #mobilfunk
5 #o2
6 #africa
6 #location
6 #twittermigratin
6 #yakima
7 #cyberwriter
7 #egov
7 #iot
7 #metapresses
7 #microscopy
7 #vinyl
7 #worldcup2022
8 #hike
8 #stromverbrauch
8 #trans
9 #blackincyber
9 #calligraphy
9 #catholic
9 #graphicdesign
9 #kommunen
9 #nopag
9 #splunk
10 #embedded
11 #womenintech
13 #markdown
13 #stickers
15 #emacs
15 #freebsddev
18 #homelab
19 #cheatsheet
19 #polish
19 #riskmanagement
23 #lab

So since 13.11.2022 I have collected > 6k toots/boosts.

Hashtags trending in my timeline for this period (only with count >= 100):

sqlite> select count, "#" || tag FROM tags WHERE count >= 100 ORDER BY(count);
101 #rust
102 #python
103 #opensource
104 #security
105 #linux
117 #birdsite
123 #freebsd
129 #threatintelligence
132 #dfir
140 #photography
142 #privacy
152 #ransomware
153 #fuzzing
155 #activedirectory
158 #malware
164 #twittermigration
200 #hachyderm
213 #threatintel
232 #fediverse
354 #twitter
403 #introduction
409 #cybersecurity
647 #mastodon
685 #infosec

Enjoy!