This is a lovely idea, really well executed.

Using a variety of techniques, a team has developed the Expression Flower that senses when it is being smiled at and then opens up to smile back at you. Powered by a Raspberry Pi, the flower is coded using Google’s IoT platform, Android Things. There’s a camera module at the centre which reads in image data, passes it to the Pi which itself uses the ML Kit learning ‘machine’ from Google. Oh, if you wink at it, it closes up again in a bashful kind of way! The entire project, which uses 3D printing and laser-cutting, has been open sourced and documented over on Hackster.io.