xDict = {0: 0, 1: 1.2, 2: 2.4, 3: 2.4, 4: 1.2, 5: 0, 6: -1.2, 7: -2.4, 8: -2.4, 9: -1.2}
yDict = {0: 3, 1: 1.8, 2: 0.6, 3: -0.6, 4: -1.8, 5: -3, 6: -1.8, 7: -0.6, 8: 0.6, 9: 1.8}

So for 3.1415

Plot starts out at coordinate x=0, y=0
the three (3) will be defined as x=2.4 y=-0.6 from previous location
- Decimal is skipped -
the one (1) will be defined as x=1.2 y=-1.8 from previous location
the four (4) will be defined as x=1.2 y=-1.8 from previous location
the one (1) will be defined as x=1.2 y=-1.8 from previous location
the five (5) will be defined as x=0 y=-3 from previous location

The Pi_Plot(pyQtGraph)Color.py just adds dynamic color to the plot. The total number of digits of PI() calculated is split into 10 data buckets and each bucket is assigned a different color. So, once plotted, the trace will have ten (10) different colors.