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🌠 Lesson 4.3: Capstone Part 1 — Plan It & Build the Core

This is the big one, and it comes in two parts. Today you and your child plan a game on paper, then build the playable heart of Star Catcher: stars rain down and you catch them in a bowl. Next lesson you'll add lives, Game Over, and a launch day.

📚 What You'll Learn

By the end of this lesson, you will be able to:

  • Plan a game before coding it: brainstorm, pick one idea, sketch it, and list the pieces
  • Fill in a one-page game design card together with your child
  • Build the smallest playable version of a game first
  • Combine clones, variables, and your reset game My Block in one project
  • Share the work with your child as director and typist

Estimated Time: 40 minutes  •  Project: Star Catcher, Part 1 — a bowl that catches falling stars and keeps score

Ages 5–7 (with help) Ages 8–11 Ages 12+
In This Lesson

🎬 What we're building

In Star Catcher, stars fall from random spots at the top of the screen and you slide a bowl with the arrow keys to catch them. Each catch adds to your score; each miss costs one of three lives; at zero lives, GAME OVER. It uses nearly everything you've learned:

Game pieceIdea it usesWhere you learned it
Bowl moves with arrow keysforever + if + key pressedLesson 2.3
Score and livesVariablesLesson 3.2
Lots of falling starsClonesLesson 4.1
One block that resets the gameMy BlocksLesson 4.2
Game Over appearsBroadcastsLesson 3.1

That's a lot for one sitting, so it's split on purpose. Today: plan it and build a playable game with a score. Part 2: lives, Game Over, and a launch.

🎓 Learn It: Plan before you code

The most important skill today isn't a block; it's planning. Games started by dragging blocks tend to grow too big to finish. Five minutes on paper prevents that:

  1. Brainstorm. Lots of ideas, no judging. Silly is welcome ("a taco that dodges forks!").
  2. Pick ONE small idea with one main action: catch, dodge, jump, or chase. Other ideas go on a "someday list."
  3. Sketch it on paper. Where does the player start? What moves? How do you score, and how do you lose?
  4. List the pieces as a checklist. Every sprite, variable, and rule becomes a line to tick off.
  5. Build the smallest playable version first, then add one thing at a time.

That last step is a loop game studios use too:

flowchart TD A["💭 Brainstorm
lots of ideas"] --> B["☝️ Pick ONE
small idea"] B --> C["✏️ Sketch it
on paper"] C --> D["📋 List the pieces
as a checklist"] D --> E["🧱 Build the smallest
playable version"] E --> F{"🧪 Test it:
does it work?"} F -->|Not yet| G["🐛 Fix one thing"] G --> F F -->|Yes!| H["➕ Add ONE
new feature"] H --> F style A fill:#FFBF00,color:#4d3800,stroke:#333 style B fill:#FFBF00,color:#4d3800,stroke:#333 style C fill:#9966FF,color:#fff,stroke:#333 style D fill:#FF8C1A,color:#fff,stroke:#333 style E fill:#4C97FF,color:#fff,stroke:#333 style F fill:#5CB1D6,color:#fff,stroke:#333 style G fill:#FF6680,color:#fff,stroke:#333 style H fill:#59C059,color:#fff,stroke:#333

Test after every addition, and any bug came from the one thing you just added.

🌱 Growth mindset: small is how big things start

Shrinking a grand idea into "a bowl catches stars" can feel like a letdown. It isn't. Every big game started as a tiny, plain version that barely worked. Say it out loud when you trim the plan: "We're not throwing this idea away. We're building the part we can finish first." Your child learns that a finished small thing beats an unfinished giant one, and learns it by watching you.

🎓 Learn It: The game design card

Copy this card onto paper and fill it in together. Our Star Catcher answers are on the right.

🃏 Game Design Card

QuestionOur answer (Star Catcher)
Game nameStar Catcher
Who is the player?A bowl at the bottom of the screen
Controls: how do you move?Left and right arrow keys
What else moves?Stars fall from random spots at the top
How do you score?Catch a star: +1 point and a "pop" sound
How do you lose?A star hits the ground: lose 1 of 3 lives
What happens at the end?GAME OVER appears and the game stops
Smallest playable versionBowl moves + stars fall + catching adds score
Someday list (later ideas)Faster stars, rocks to dodge, high score, levels

✏️ Sketch box: leave space to draw the stage: bowl at the bottom, stars at the top, arrows for movement.

Then write the checklist of pieces: Bowl sprite, Star sprite, Game Over sprite, score, lives, a reset game block, and a game over broadcast. Seven ticks. Today covers all but the two Game Over pieces. The someday list becomes Part 2's bonus menu.

🛠️ Try It: Build the core game

Press the green flag after every step. Times are for a parent alone; with a child driving, expect about double, and that's fine. These seven steps build the smallest playable version.

  1. Set the stage (about 4 min)

    Start a new project and delete the cat (right-click → delete). Use Choose a Sprite to add a Bowl and a Star, and pick a night-sky backdrop such as "Stars."

  2. Make the variables (about 3 min)

    In Variables, click Make a Variable, name it score, and choose For all sprites. Repeat for lives (it gets used in Part 2). Leave both ticked so they show on the stage.

  3. Build the reset game block on the Bowl (about 6 min)

    Select the Bowl. In My Blocks, click Make a Block, type reset game, and click OK. A pink define hat appears. Snap these under it:

    It's the same block from Lesson 4.2.

  4. Make the Bowl move (about 6 min)

    Still on the Bowl, call reset game once, then check the arrow keys forever:

    Click the green flag, then the stage, and tap the arrows. The bowl slides; score and lives show 0 and 3.

  5. Turn the Star into a star factory (about 5 min)

    Select the Star. The original never falls; it hides and makes clones, like a factory behind the curtain:

    The first wait lets the player get ready; the random wait keeps the rhythm unpredictable.

  6. Make each clone fall (about 6 min)

    Add a second Star script. Each new clone jumps to a random spot along the top, appears, and falls:

    Stars rain down! They pile up at the bottom for now; Part 2 turns misses into lost lives.

  7. Catch the stars (about 5 min)

    Inside the clone's forever loop, under change y by -5, add a catching check. First add Pop (or any sound) in the Star's Sounds tab.

    Why not just start sound? Deleting a clone silences its sound, cutting off the pop. Hiding makes the star vanish instantly; until done lets the pop finish before the clone goes.

✅ Checkpoint: it's a real game!

Play it. Stars fall, you catch them, the score climbs: a complete game. Everything in Part 2 is an addition.

💾 Save your project before you stop

Type Star Catcher in the title box above the stage. Signed in? Choose File → Save now; it waits in My Stuff. Not signed in? Choose File → Save to your computer and note where the .sb3 file lands. Part 2 opens exactly this project.

🐛 Common problems & fixes

What you seeLikely causeFix
The bowl won't moveThe stage lacks keyboard focus, or the ifs sit outside the foreverClick the stage once; put both ifs inside the forever
A star sits frozen at the top, or none appearThe original is visible, or the clone script lacks showOriginal: hide first. Clone script: include show
Stars pile up at the bottomNothing removes missed stars yetExpected today; Part 2 fixes it
Catch sound is cut off or silentThe clone is deleted while its sound is still playingUse hide → play sound … until done → delete this clone
Score doesn't reset on replayreset game isn't called, or it's inside the foreverPut reset game right under the Bowl's green flag, before the forever
Test after every step. If it worked a minute ago and doesn't now, the bug is almost certainly in the last thing you added.

💬 Teach It: Build it as a team

The child directs; the parent types when needed

Your child can own the decisions before they can do every drag. They're the director: they decide what the game is, how it looks, and whether a change is "right." You're the typist, taking the mouse only for fiddly bits and only when asked:

"You're the boss of this game. I'm your helper. Tell me what you want, and if you want me to do a tricky part, just say 'your turn.'"

When you do take the mouse, narrate and hand it straight back:

"Okay, I'm finding 'change x by'... it's in blue Motion... snapping it inside the if. Your turn — press the flag and see if it worked!"

Planning out loud

Treat the design card as a conversation, not a form, and write their answers in their words:

"If you explained this game to your friend, what would you say? How do you win? How do you lose? What's the one thing the player does most?"

When a big idea arrives mid-build, park it kindly:

"Ooh, rocks too? Someday list! We'll add it once the stars work."

Play for a minute after every working step. "You do it" usually means it's time to save and stop.

👧 Ages 5–7

They draw the design card, choose sprites and sound, and press every green flag. You drag while they direct. Catching stars with a score is a complete game at this age.

🧒 Ages 8–11

They fill in the card and do most of the building. You read each step aloud and help nest blocks inside ifs and loops.

🧑 Ages 12+

Give them the card and checklist, not the steps. Let them work out the scripts, then explain the "star factory" back to you.

🌟 End on a high

Finish with a high-score round: each of you plays once and your child writes the scores on the design card. A number to beat makes Part 2 something to look forward to.

🎯 Quick Check

Question 1: Your child has a huge game idea with dragons, shops, and ten levels. What's the best first move?

Question 2: In Star Catcher, why does the original Star sprite hide and only make clones?

Question 3: When a star is caught, why does the clone hide and play sound Pop until done before delete this clone?

📓 Learning Journal

Take five minutes to write it down

Tape your design card in next to today's entry.

  1. Key concepts: What is the "smallest playable version," and why build it first?
  2. What clicked: Which piece fit better than expected: the star factory, reset game, or the catch check?
  3. Questions & confusion: Which of today's steps could you not yet rebuild from memory?
  4. Ideas to try: Which someday-list item do you want to add first in Part 2?
  5. Progress & feelings: How did director/typist feel? When was it hard not to grab the mouse?

💡 Teach It tip: Have your child glue the design card into their coder's notebook with today's best score beside it.

Summary & What's Next

🎓 Key Takeaways

  • Plan before you code: brainstorm, pick one small idea, sketch it, and list the pieces as a checklist.
  • A design card turns an idea into a to-do list; a someday list keeps big ideas parked.
  • Build the smallest playable version first, then add and test one feature at a time.
  • A hidden original acts as a clone factory; each clone falls, checks for a catch, and deletes itself.
  • Your child directs; you type only when needed.

🏅 What You've Accomplished

  • Planned a game on paper with a design card and checklist
  • Built a playable Star Catcher with movement, clones, and score
  • Used your own reset game My Block in a real project

📋 Before the Next Lesson

  • Save the project as Star Catcher and check you can find it again
  • Play a few rounds and write down the best score
  • Write your journal entry

❓ Common Questions at This Stage

We only got as far as the moving bowl. Are we behind?

Not at all. Planning plus a working bowl is a solid sitting. Save it and start at step 5 next time.

My child wants to make a totally different game instead. Is that okay?

Yes, and it's a great sign. Use the same routine. Dodging, catching, and collecting games all use this clone-and-touching pattern, so the steps still apply.

The stars piling up at the bottom bothers my child. Can we fix it now?

If they're eager, peek at step 8 in the next lesson. Otherwise, call it a cliffhanger: "Next time, missed stars cost you!"

🔭 Looking Ahead

In Lesson 4.4: Capstone Part 2 — Lives, Game Over & Launch Day, you'll open this saved project and finish it: missed stars cost lives, a game over broadcast stops everything, and a bonus comes off the someday list. Then comes launch day, when your child shows the game off.

💛 Encouragement for the Journey

You turned a paper plan into something your child can play. Going from nothing to something is the hardest half of any project, and you've done it.

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