nicer multi-trial symbolic variables

This is a simple simulation of a PP:

• Cleaned up code
• Better figure, more advanced plot, more informative, better aesthetics
• More corrected math
• Unicode symbols used as variable names
• Improved program design and nice patterns
• Multiple-trial implemented
• More trials added to the figure
• Experimental visualisation
  (No symbolic yet. Also further improvements are don in the other repo (clone of the bit bucket)