The ability to transmit information using radio waves is built into the micro:bit.
The means that micro:bits can send to, and receive information from, other micro:bits.
Test out sending and receiving messages, then think about what problems you could solve by transmitting information.
By default, all micro:bits can see each others' messages.
Choose a group number unique to your project, so you don't get any interference.
Collect a second micro:bit to use this code.
Keep track of which micro:bit sends messages, and which will receive them!