Pretty simple PCB meant for testing a chip based on the Silicon Labs BGM220S series of chips. In this case I was working with the BGM220SC12WGA2 for my senior design project. There are pads for allowing this chip to work as a standalone Bluetooth + Microcontroller and as just a Bluetooth module. There weren't very many difficulties in creating this PCB except for some small quirks with creating non-rectangular SMD pads for the footprint of the chip and sometimes assigning things to ground that are not connected to ground in the schematic.