this is toy ventilator made out of a large smart water bottle and a 3d printed part. 

the ventilator itself is just two parts (4 if you multicolor print) that connect with a filament-pinned hinge. 

the chest piece is made from a smart water bottle or similar bottle so that its clear and somewhat flexible. see image for how to cut the bottle. the edges of the cut pieces overlap and light up behind the branches of the frame. assemble with very hot, hot-glue. add ribbon and/or velcro for straps. optionally attach to the ventilator with a length of 8mmOD tubing of your choice