This is a key chain tag that uses microfluidics to spell out whatever you customize it to say (usually a name - max ~9-10 letters, that are best when capatilized - let me know if you need further customization). It is two parts and should be assembled by placing the like bar channels too each other (this wil leave 2 tapered ports facing outward). this can be secured either mechanically or with something like super glue (careful about not getting it into the channels by using veryy little far away from channels and after dry fittings, and make sure the surfaces are clean and flat, to minimize gaping), or other liquid adhesives (since super glue can result in unsightly clouding )
Microfluidics use channels typically ~.5mm or smaller (sub millimeter) to transport fluids causing uniqe behavior as laminar flow starts to dominate over turbulent flow and other factors such as surface tension, viscosity, and other capillary effects begin to dominate. 3d printers can now reach levels where it begins to be practical to have microfluid channels printed rather than cut into PDMS layers and sandwhiched . Although this keychain is still a combined layer due to limitations in custom maker (it uses a top down projection rather than a solid subtraction), 3d print escape hole requirements (Shapeways clears requires 2mm min escape holes), etc, it may be possible to get single print microfluid chips from shapeways with some reworking (I will try later).
This is an untested model made for the custom maker keychain challenge, so I can not gaurntee it will work, and it will have to wait for a few tests to fully charcterize the behavior (i.e. does the resin/acrylic print material affect the flow, is the channel smooth enough etc.), even then it should still result in a keychain tag with your text (like name). it can still result in some intresting mixing properties so I would suggest for a cool experiment of using two different food coloring dyes in different water sources and adding them from different ports (different variations, clear water then add the drop directly to different ports, mix dye and water then add, let one flow first, add both at same time, etc, mix oil and water, or other simple non reactive fluids)