Here is physical interface to virtually paint like Pollock.
This is a short explanation of how it woks:
The actual color was replaced by light.
The brush is made from wood. Inside it: Accelerometer, Arduino-mini, EasyRadio RF-Module, RGB-LEDs.
The accelerometer data is transmitted to the computer over serial(over air).
The computer sends back the color information for the RGB-LEDs.
The color is changed by pointing the brush into the paint buckets.