Despite being mass-produced, Klaas discovered irregularities in the green glass bottles. Every time they were cut in half, the thickness of the glass seemed to vary and be different. To emphasize these differences, Klaas built his own glass-blowing installation consisting of a customized oven and a compressor. By first heating the bottles in the oven and then gently blowing some air in with the compressor, the glass bulges more in the thinner areas and less in the thicker areas. This gives the bottles their new, unique shape. Through much experimentation with heat and pressure differences (and later countless explosions and cracked bottles), Klaas finally mastered the technique to create a coherent family of individually shaped green bottles.






































