Wavy window glass - what could be the reason for that?

Hello dear experts,

on the way between our construction site and our current apartment, I always drive through a new development area with neat single-family homes from the years 2017/18
What has caught my attention so far while passing by:

[*]There is a house where all the window panes somehow look "wavy". In comparison, our new windows in the renovated old building are "flat". I have hardly seen such waviness until now.... where does it come from?

[*]The windows in our old building look rather purple from the outside (triple thermal insulation/security glass Weru SupraTherm Secur (0.38 PVB), glass structure: 6* VSG* / 18 A / 4 / 18 A / 4*) and you can see inside. I do not find that problematic, but is that due to the VSG? In the mentioned new development area, I see both, more "purple" looking glass but also the classic "transparent" ones. Is there an explanation for this?

Interested regards,

Hexle

Wavy can either indicate defective or explicitly desired wavy glass.

In my opinion, most window panes are nowadays produced using the float process, which results in a very flat surface.

The purple tint comes from the coating of the glass, whose purpose is to allow more blue light into the interior of the house, thus providing more daylight inside while maintaining thermal insulation. (usually with triple glazing)

It can also be that the window panes are anti-reflective. Then they shimmer purple to green. It depends on what the builder ordered or what the construction company has as standard.

Windows that do not shimmer purple simply have no coating or are often only double-glazed.

Google "Newton's rings"