The Pirate Captain's Treasure Map: Mastering Finite State Automata (FSA) with the "Island Hopping" Game

不插電有限狀態自動機教案：海盜藏寶圖跳島遊戲，讓孩子畫出自己的狀態圖，認識狀態與轉移。改寫自 CS Unplugged Treasure Hunt，附地圖與引導，適合國小高年級。

Imagine you are participating in a thrilling pirate treasure hunt. Your goal is to find the legendary "Treasure Island." But there is a huge problem: you don't have a map.
In Computer Science, when we don't know exactly how a system is supposed to work, we often draw a specific type of diagram to help us think. Today, we are going to take children from a "stumbling in the dark" adventure to mastering a powerful tool in Computer Science—the Finite State Machine (FSM).

Phase 1: The Fear of Getting Lost

First, let the children experience the dilemma of having "no map."

  1. Scenario Setup:
    • Imagine there are seven islands controlled by pirates right in front of you.
    • You are standing on the first island. There are two ships docked in front of you: Ship A and Ship B.
  2. The Key Challenge:
    • 你手上沒有航海圖，完全不知道這些船會開去哪裡。每座島各有一位「島主」（拿著一張蓋住的指路卡），你抵達該島之後，才能問到 A、B 船各開往哪裡。
    • You can only choose to hop on one of the ships.If you are lucky, you might get one step closer to the treasure.If you are unlucky, you might be shipped back to the starting point, or just sail in circles around the same island.
  3. Guide the Feeling:
    • "If we just randomly hop on ships like this, doesn't it feel like walking through a maze? Are we going in circles without realizing it?"
    • This is exactly the state of a computer without instructions—confused and ineffective.
注意：這張指路卡取自原教材「三座島」的示範地圖，路線與下方的正式七島地圖不同，僅示意每座島都有一張這樣的卡片。

Phase 2: Drawing Your Nautical Chart

Since we are afraid of getting lost, let's draw a map by ourselves. This is the process of converting "experience" into "logic."

  1. Start Drawing:
    • Take out a piece of paper. Draw every island you arrive at as a "Circle" (Dot).
    • Draw the Ship A or Ship B you took as an "Arrow" (Route) connecting the islands.
  2. Building the Model:
    • When you draw this diagram, you are actually constructing a Computer Science model!
    • Islands (Circles): Computer scientists call these "States."
    • 搭船（箭頭）： 箭頭本身代表「轉移 (Transition)」；箭頭上的船名（A 或 B）就是「輸入指令」。
    • The Whole Map: This is the "Finite State Machine (FSM)." It clearly defines what happens to the system under specific conditions (which island you are on) when receiving specific instructions (which ship you take).
圖例：箭頭指入的 1 號是起點（海盜島）；畫兩個圈的 7 號是終點（金銀島）。

Phase 3: Connecting to Daily Life (Concept Connection)

Turns out, a watch is just a Pirate Island

Now, let's apply this pirate map concept to a digital watch on a child's wrist (or the air conditioner remote at home). You will discover they are actually the same thing!

  1. Life Metaphor:
    • Initial Island (State): The watch currently displays the "Current Time."
    • Taking Ship A (Input): You press "Button A."
    • Traveling to a New Island (Transition): The watch screen changes to "Stopwatch Mode."
  2. Continuous Operation:
    • Taking Ship B: On the "Stopwatch Island," pressing "Button B" makes the watch start counting (State Change).
    • Taking Ship A Again: If you press Button A one more time, you might jump to the "Alarm Settings" island.
    • Back to Start: Keep pressing A, and eventually, you will find yourself back at the original "Time Display" island.

Phase 4: The Takeaway & Reflection

The User Manual IS Your Map

  • Parent's Summary:"Look, the logic of operating this watch is exactly the same as the pirate islands! The 'Instruction Manual' that comes with electronic products is actually the 'Nautical Chart' we just drew."
  • 思考挑戰： 「如果有一座島（狀態），不管搭 A 船還是 B 船都出不去（永遠停在原點），在海盜遊戲裡這叫『死路』；在電腦或手錶裡，這叫做什麼？」 (答案：不管再按什麼都達不成目標——機器沒有壞，只是被規則困在「陷阱狀態」裡)
  • Let's try drawing a State Diagram for Super Mario!
    • Initial State: Small Mario.
    • Input Instruction A (Eat Mushroom): Transforms into Big Mario (State Change).
    • Input Instruction B (Hit a Turtle):
      • If you hit a turtle on "Small Mario Island" $\rightarrow$ You die (Game Over).
      • If you hit a turtle on "Big Mario Island" $\rightarrow$ Turn back into Small Mario (Injured but not dead).
    • The Teaching Highlight: Let the child discover: Why is the result different even though the action was the same ("Hitting a Turtle")? Because your "State" at that moment was different!

Through hand-drawing the connections between islands, we learn how to simplify complex system behaviors into visual logical models. The Finite State Machine allows computer scientists to precisely design software interfaces and hardware control logic.

Reference :csunplugged finite state automata

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