This is derived from the Bitcoin Matrix, so setup is similar
- https://learn.adafruit.com/bitcoin-value-rgb-matrix-display/using-matrixportal
- https://github.com/adafruit/Adafruit_Learning_System_Guides/tree/master/Bitcoin_Matrix
General rule is green if up and red if down.
The top-left value is the price in regular market hours.
Bottom-right value is the price in pre/post trading.
Regular and pre/post values will be brighter if we're in those hours.
The bottom-left percent is the change since the regular market opened. If we're in pre-market trading, then it's the pre-market percentage change.