I made them from transparent pla with 1mm thick walls. You can see the insects walking around inside them:
see-thru_640x270.jpg


It's an example of how you can make fairly complex shapes without supports.

The beauty of 3d printing is that you can think of a thing that nobody else in the world has ever though of and inside a couple of hours actually hold it in your hand :-)

I'm currently printing a tool to smooth down masking tape.
Got a bunch of window frames to mask off - and something better than my gloved finger (they are outside) to get a really good flat application of tape was needed.
I've actually made three all slightly different in design to see which is best :-)