
The game Lemmings involves critters with fairly simple brains. So simple
that we are going to model it using a finite state machine. In the
Lemmings' 2D world, Lemmings can be in one of two states: walking left
(walk_left is 1) or walking right (walk_right is 1). It will switch
directions if it hits an obstacle. In particular, if a Lemming is bumped
on the left (by receiving a 1 on bump_left), it will walk right. If it's
bumped on the right (by receiving a 1 on bump_right), it will walk left.
If it's bumped on both sides at the same time, it will still switch
directions. Implement a Moore state machine with two states, two inputs,
and one output (internal to the module) that models this behaviour.
areset is positive edge triggered asynchronous reseting the Lemming
machine to walk left.

module TopModule (
  input clk,
  input areset,
  input bump_left,
  input bump_right,
  output walk_left,
  output walk_right
);

