====== 2020-01-17 - burning visual patterns on CDs ======

around mid of my studies we had a lab with a very unusual task -- to record data on a [[wp>floppy disk]], that would create a magnetic pattern. these were checked only conceptually (i.e. if all required steps were taken into account), as it is hard to check these very weak, magnetic patterns w/o specialized equipment (and probably quite a bit of a free time ;)). we thought it would be nice to do the same kind of a trick but with a [[wp>compact disk|CD]] -- this time it would be visual, thus trivial to verify correctness. unfortunately back at that time cd recorders were still relatively expensive and not a common thing to have, thus we stopped there... and never got back to it again.

recently i have talked with a colleague of mine at work about that... the concept sound to be easy to come across, and thus not likely no1 ever did that... and guess what -- some1 made a [[https://www.instructables.com/id/Burning-visible-images-onto-CD-Rs-with-data-beta|PoC that created visually visible images on burned CDs]], by tinkering with the data stream to be recorded. ;)