The first half of the course will present an overview of operational semantics (specifically context-sensitive rewriting semantics) and PLT Redex. It will cover the basic mathematics behind operational semantics as well as basic properties that semantics should have and how they are used.

Come up with 5 legal boards and, for each of those boards, one illegal move and one legal move (ie, a total of 15 instances of G).

(define-language bgm
  (G (B ... (B D ...) ... color)) ; Game state
  (B (HB HB)) ;; white pieces, then black pieces
  (HB (C ...)) ;; one C for each checker
  (C N home bar) ;; where the checker currently is
  (N number)
  (D 1 2 3 4 5 6) ;; die rolls 
  (color b w))

Notes:

• To be legal for their game, there must be at least one B in a game state, but ignore this for your test cases
• White moves by addition, and black by subtraction
• With the exception of bopping, taking a die roll is always a complete move
• Bopping happens in stages; first the white & black piece sit on the same spot and the die roll is removed. In the second stage the bopped piece is moved to the bar and the color changes.
• This is the initial B for the actual game:
  

  ((1 1 12 12 12 12 12 17 17 17 19 19 19 19 19)
   (24 24 13 13 13 13 13 8 8 8 6 6 6 6 6))