World 5 · Messages · Guide 2 of 5Free guide
Can one block start another?
Your send block can start a program that isn't yours.
Meet the send block again
Last time you waited for a message. This time you send it. Your send block does not move your character at all. It starts a different program — every program waiting under a 📬 hat, all at once. And where you put it in your program decides when they start.
Send it too soon, and the other program starts too soon.
See it work
One hen, two chicks. The hen sends one message. Count how many programs start.
🐤
🐥
One send block, two programs started — both on the same beat. A message goes to everyone who is listening for it.
Your turn
Now you're the programmer.
Can you send the train on its way?
Walk the 🐧 to the 🔔 and ring it, so the 🚂 goes to the 🏁.
The train's program
Blocks
Your program
Go further
What if you ring the bell first?
Move your send block to the front, so it runs before the penguin walks. Press play. The train hears the bell straight away and leaves — while the penguin is still crossing the track. Same blocks, wrong order. When you send matters as much as what you send.
For grown-ups
One program triggering others is called an event-driven design — when one part of an app finishes, it announces it, and every part that cares starts its own work.
Keep going
Next in World 5Can characters take turns? →Where this goes
Make a game other kids can play
The blocks on this page are a first taste. In a Kubrio project your kid builds a real game — powers, triggers, levels and all — and other kids get to play it.