There were curtains on the G-model Pantaloons. Their idea is that the elastic band or strip of cloth, which is a waist line, sit down two triangles, which play the role of the front and back of the panties. Placed in the form of curtains, they can adjust themselves in higher or lower, opening or closing parts of the seats bikini.
The lower waist and the ability to adjust the width of the front and rear, as it turned out, very comfortable and sexy thing. So you can open the front of almost down to the pubic hair, and push back the most, thus revealing the buttocks. And all this is possible due to the fact that the back and front parts are not attached to the waist line, but as it wore on her. This structure brought the panties to the future of their thongs. This fact makes it incomprehensible to stop in their development in the seventies.
Only after ten years in the late eighties like bikinis were developed when it became the fashion for mini - shorts, who had a narrow front end and a high waist. This mode is also triggered the development of pubic hair removal so that you can open as much a part of the front.