Here’s a no-PCB Arduino ... and an LED. This is modeled after the Lilypad hardware, and fits nicely on top of the plastic case of the microcontroller, allowing it to be used in a breadboard ...

[Aniss Oulhaci] demonstrates this with a simple HF SDR receiver built on a breadboard. An Arduino is used to control the SI5351 clock generator, which in turn is controlled by the same program ...