control a colour field using reactive sliders, either RGB or HSV
use separate Processes for GUI and output
prototype to run on an embedded system where the operator can use
physical knobs to change the colour of an LCD panel, hence swappable
GUIColourControls
python -m venv .venv
. .venv/bin/activate
pip install -r requirements.txt
. .venv/bin/activate
python app.py