Ordinary pet bottles are so well made that it is a pity to throw them away.
So this method was invented to turn pet bottles into vases.
ISS (Ika Soumen System) started out as just an idea, but turned into a serious project.
Cover the pet bottle with the cylindrical paper made using ISS
and apply a little pressure from the top with cardboard. Once it locks in, it is done.
The form changes depending on the height of the bottle.