The tighter you hug, the brighter the bubbles glow.
The whole installation can also be intuitively controlled with an iOS device via a custom Pluck & Hug app which communicates with embedded microcontroller inside the balloons and fans over Bluetooth LE.
I developed the control software for this project for Harvey & John.
This includes the code on the embedded microcontrollers inside the fans and balloons as well the accompanying iOS application which allows control over the system.