constant N := 3;

direct variable t[N] < 2;
puppet variable e[N] < 2;
puppet variable ready[N] < 2;

// Converge to a state where one process has the token and execute the
// shadow protocol defined by the 'shadow action:' statements below.
(future & shadow)
  (unique i < N :
   i == 0 && t[i-1] == t[i]  // Bot has the token
   ||
   i != 0 && t[i-1] != t[i]  // P[i] has the token
  );

process Bot[i < 1]
{
  // i==0
  read:  e[i-1], t[i-1];
  write: e[i], t[i], ready[i];

  // Enforce this behavior within the invariant:
  shadow action: ( t[i-1] == t[i] --> t[i] := 1 - t[i-1]; );
}

process P[i <- map tid < N-1 : tid+1]
{
  read:  e[i-1], t[i-1];
  write: e[i], t[i], ready[i];

  // Enforce this behavior within the invariant:
  shadow action: ( t[i-1] != t[i] --> t[i] := t[i-1]; );
}