In 1968 Ken Thompson gave a mechanical recipe for turning any regular expression into a finite automaton: build a tiny machine for each letter, then glue them with ε-transitions — free moves that consume no input — to express choice (|) and repetition (*). The loom weaves exactly that graph in front of you.
The machine is nondeterministic: after each character it can occupy many states at once. That glowing cloud is the whole point — the automaton follows every possibility in parallel, and accepts if any thread ends on an accept state.
Pull the determinize lever and subset construction runs: each cloud of NFA states becomes a single DFA state — one lantern. The DFA is faster (no guessing) but can need exponentially more states. Weave .*a...... and watch a ten-gear NFA determinize into 129 lanterns.
The simulation stopped unexpectedly — the lesson continues without it. You can move on; nothing you did was wrong.