for when you need something more durable than a breadboard
Jenner has shared the board on OSH Park:
$17.50 for a set of three
Bill of Materials
For a non-stackable version, you can just use two standard 0.1” (2.54mm) pitch 1×40 headers, each snapped in half.
For a stackable version, you can use two of these extra-tall 2×20 female headers from Adafruit. The connectors are from the Samtec SSQ family so you could shop around for other distributors, but Adafruit has by far the best price for this particular component.
This project is released under the CERN Open Hardware v1.2 License.