Here is the official explanation of what the Activity is looking for – builders should share their builds on the very same page it is published:
We’ve seen some amazing kinetic/moving LEGO builds out there, can you move it?
This is part of a series on LEGO Ideas that gives little tasks for builders to get involved with – there are no prizes, they are just a way to get involved with building something quick for fun. Each challenge is intended to be something quick and fun, unlike the more in-depth building required for a competition or product idea.
The deadline for this Activity is August 31 at 10.00am CEST.
The last LEGO Ideas Activity focused on brick separators, encouraging fans to incorporate the frustratingly common pieces into a MOC.