To have this prototype was very helpful to give an overview of the total of the Solar Bathroom Box. It looked good, was stable because of the four 'legs'. The size also seems about good.
The wall thickness should be reduces from 3 cm to 2 cm. to lower the weight from 35 kilo. The top is now too sharp for folding over the plastic liner bag. Thanks to a different split in parts it can become rounded off. The core should have less taper and a flat bottom decorated with mosaic.