The current design of the WaterColorBot frame does not permit vertical operation. The rods glide on sliders that are held down to the frame by gravity. It would be possible to design new rod-end sliders that would constrain the rods vertically, in which case vertical operation would be possible.
For the originally intended application– using watercolor paints — only horizontal operation is suitable, as we also assume that the water in the little dishes can be held down by gravity. ;)
