As a model making process we used rotational moulding even though most bottles are blow moulded industrially. Yet, the rotational moulding was easy to experiment with in our workshops and realized similar shapes. We used polyurethane, which was poured into a negative mould made of silicone. The moulds were clamped in a frame which is rotated biaxially – our DIY machines. This three-dimensional rotation causes the plastic to settle on all outer walls. The hardening plastic forms a hollow body.