Thanks...the start was "relatively" easy... compared to the latest "Challenges" took the same time finish No 63 equals the time doing the inner 4*4 square PLUS the rim...
BUT with only one screen, Ingame Overlay showing this pic fullres PLUS Game not very visually helpful.
When i remember back four years, i did not place even 50 pieces and did not get this challenge done... But after saving Ultimate and Gold pieces, i was able to get back some challenges, but this is SO hard... But there is still progress, 15 pieces average 45-60 min...

https://steamuserimages-a.akamaihd.net/ugc/1825653570822238133/BC6061F5DE6C66EDACAEBEDBCE7C414E0B22119A/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Thanks, doing it now and these lines are really helpful

how did this help ?

It unlocked the "1 Challenge Complete" and "Challenge 1 Complete!" achievements, although as of now you cannot recieve the latter one due to the Challenge being timed.

What achievement does this unlock?

Thanks!