Gridworlds
MASA includes several single-agent tabular gridworlds. They all use discrete states, discrete actions, and explicit stochastic
transition models. Every environment in this family exposes a full transition matrix via get_transition_matrix().
Shared Action Convention
The gridworld helpers use the same five actions throughout:
0: move left
1: move right
2: move down
3: move up
4: stay in place
When slip is enabled, the intended action is taken with high probability and the remaining probability mass is spread uniformly over
the other actions.