 Let's take a look at this simple automaton I made. Its purpose is to check that a given sentence starts with a capital letter and ends with a full stop. It may seem a little daunting right now, so let's look through it step by step. First, we can see that this diagram has four circles labeled 1, 2, 3 and 4. These are the different states of our automaton. Between these states are arrows labeled with U for uppercase characters, S for a full stop and L for lowercase characters as well as any other punctuation. These represent transitions from one state to the next. For example, if we are at state 1 then the U arrow will transition us or move us to state 3 while the LS arrow would transition us to state 2. Here LS just means that both L and S result in the same transition. Now note that the arrow on the far left is not labeled and does not transition between states, instead only entering state 1. This tells us that state 1 is the start state. So whenever we run through this automaton we always start from here. Lastly, state 4 on the right is two circles, telling us that this is an accepting state. For this example, acceptable sentences that begin with the capital letter and end with a full stop will result in transitions that end at this state. We can have any number of accepting states. Even the start state can be an accepting one, but we can only have one start state.