The required components are:

  • Two cork pot coasters

  • Four silicone pot coasters (3x red, 1x gray)

  • A thin layer of black sponge for additional "bounciness"

  • Glue

It was a quick and easy build that came together nicely, and now I have a reasonably-priced and conveniently sized drum practice pad.

The raw components for the build, as purchased at a Seria 100-Yen shop.
Top view of the thick layer of the resulting drum practice pad.
Top views of the red (thick) and gray (thin) layers of the resulting drum practice pad.
Profile view of the resulting drum practice pad.