Your first blocks: drag, snap, click

Time to actually build. Scripts in Scratch are made by dragging blocks and letting them snap together — no typing, no punctuation, no fear.

Dragging and snapping

1. Click Motion in the palette. The blue blocks appear.
2. Point at move 10 steps, hold the mouse button down, drag it into the middle of the code area, and let go.
3. Now drag turn ↻ 15 degrees and drop it just underneath the first block. As you get close, a pale shadow appears — that is Scratch telling you the blocks will snap. Let go, and they click together like Lego.

You just wrote a two-line program. Congratulations.

Clicking to run

Click your stack of blocks. The cat moves and turns, and a yellow glow runs round the script while it works. That glow is the computer showing you where it is in your instructions.

This is the superpower of Scratch: you never have to wonder what a block does. Drag it out, click it, watch. Curiosity is a legal debugging strategy here.

Changing the numbers

Every white oval inside a block is a number you can change. Click the 10 in move 10 steps, type 100, press Enter, then click the script again. The cat leaps. Change it to -100 and he goes backwards. Numbers in Scratch are yours to play with, and playing is how you find out what blocks mean.

Taking blocks apart

• Pull a block out of the middle: drag it away — everything below it comes with it. Drop the leftovers back on afterwards.
• Delete a block: drag it back into the palette on the left. It vanishes.
• Copy a whole stack: right click the top block → Duplicate.
• Undo a mistake: Edit menu, or the keyboard shortcut your instructor will show you. There is always a way back.

The blocks for today

From Motion: move 10 steps, turn ↻ 15 degrees, turn ↺ 15 degrees, go to x: 0 y: 0.

From Looks: say Hello! for 2 seconds, change size by 10, next costume.

From Control: wait 1 seconds — small, humble, and the block that makes everything else watchable. Without a wait, the computer does all your steps so fast that you only ever see the last one.

Try it now

Build this stack, in this order, and click it:

move 100 steps → wait 1 seconds → turn ↻ 90 degrees → wait 1 seconds → say Hello! for 2 seconds

Then change one number and run it again. You have just discovered the whole loop of programming: build, run, look, change, run again.