In the two attached pictures - found them on a youtube video, containing just these 2 reference -, the creator seem to have modeled a wristwatch by revolving the lugs, crystals, bezel etc… Either by subtracting or adding (I guess?)
However, there one area that remains a complete mystery. If you look between the lugs, two tangent circles have been drawn and in the second picture (highlighted in yellow) seem to match perfectly with the way the lug edges chamfer. How was this possible?
Many thanks