Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2008712.

These little plates are intended to funnel the sound from the speakers toward the user. They are attached to the laptop with high strength double-sided tape. Overall, these improve the audio when the computer is on my lap, which is the purpose.

I put a BSD license on this thing, so do whatever the hell you'd like with it. :-)

UPDATE: I have made another version of this part that is thicker and sturdier than the original, which may improve the performance. This additional thickness may cause the rubber pads on the bottom of the laptop to not make contact on flat surfaces.