From Test-Scratch-Wiki
A Stack block is a rectangular block that is shaped to fit above and below other blocks. Stack blocks make up the majority of the blocks available in Scratch, being available in every category except Operators and PicoBoard Blocks.
When 2 stack blocks are connected to form a script their commands will run from top to bottom, unless turbo mode has been activated in which case the script runs all blocks at the same time.
Blocks
There are 77 stack blocks in Scratch 2.0, including extensions, as follows:
- Move () Steps
- Turn () Degrees (Clockwise)
- Turn () Degrees (Counter-clockwise)
- Point in Direction ()
- Point Towards ()
- Go to X: () Y: ()
- Go to ()
- Glide () Secs to X: () Y: ()
- Change X by ()
- Set X to ()
- Change Y by ()
- Set Y to ()
- If on Edge, Bounce
- Set Rotation Style ()
- Say () for () Secs
- Say ()
- Think () for () Secs
- Think ()
- Show
- Hide
- Switch Costume to ()/Switch Backdrop to ()
- Switch Backdrop to () and wait
- Next Costume/Next Backdrop
- Change () Effect by ()
- Set () Effect to ()
- Clear Graphic Effects
- Change Size by ()
- Set Size to ()%
- Go to Front
- Go Back () Layers
- Play Sound ()
- Play Sound () Until Done
- Stop All Sounds
- Play Drum () for () Beats
- Rest for () Beats
- Play Note () for () Beats
- Set Instrument to ()
- Change Volume by ()
- Set Volume to () %
- Change Tempo by ()
- Set Tempo to () bpm
- Clear
- Stamp
- Pen Down
- Pen Up
- Set Pen Color to () (color-picker)
- Change Pen Color by ()
- Set Pen Color to () (number)
- Change Pen Shade by ()
- Set Pen Shade to ()
- Change Pen Size by ()
- Set Pen Size to ()
- Set () to ()
- Change () by ()
- Show Variable ()
- Hide Variable ()
- Add () to ()
- Delete () of ()
- Insert () at () of ()
- Replace Item () of () With ()
- Show list ()
- Hide list ()
- Broadcast ()
- Broadcast () and Wait
- Wait () Secs
- Wait Until ()
- Create Clone of ()
- Ask () and Wait
- Reset Timer
- Turn Video ()
- Set Video Transparency to ()%
- () (Custom block)
- Turn Motor On for () Secs
- Turn Motor On
- Turn Motor Off
- Set Motor Power ()
- Set Motor Direction ()
Shape
Stack blocks are fitted with a puzzle-piece like shape; the top has a notch and the bottom has a bump. Because of this shape, scripts can stretch on and on — the block tessellates.
Their shape allows them to be placed in the following areas:
- After Hat blocks
when gf clicked say [Hi.] for (2) secs
- Before/after other Stack blocks
go to [Sprite2 v] play sound [meow v] until done point towards [Sprite3 v]
- Before Cap blocks
say [Bye.] for (2) secs stop [this script v]
- Inside C blocks
forever if <(loudness) > (30)> then say [No noises.] for (2) secs
Use
As Stack blocks are shaped to allow blocks above and below them, they are used almost everywhere in a script; scripts must always have a Stack block in them to be functional. An example script:
when flag clicked repeat until <(do_Stop) = [1]> move (10) steps change [color v] effect by (25) play sound [meow v] until done if <touching [edge v]?> then say [Done!] for (2) secs stop [this script v] end end
Note how the Stack blocks are used in the script — they make up all the commands.
