A prototype very small capacity but cool looking Resident Evil inspired reservoir thing. This shouldn't hold much fluids but will look cool with some colored fluids running through it. Could be a indicator depending on the use.
If you couple the bottom and top to a reservoir respectively the same; then granted your reservoir is the same height as this indicator you will be able to see the fluid level. It works for me this way. No good videos or pictures since seeing clear fluid in a clearish pathway is a bit hard. Ill upload when I change materials.
Next derivation, I will hide the in/out ports more commonly found in commercial products. That version will use standard G1/4" fittings as well, with included printable adaptors.