Palette

This section documents each and every block in Scratch, and its precise functionality.

How to organize and refer to these blocks is up for debate. Naming headings for blocks by opcode could work (and probably will) but may seem too cryptic. Feel free to offer insight!

• Example block
• Motion blocks
  • Standard motion blocks
  • Hidden motion blocks
• Looks blocks
  • Standard looks blocks
  • Hidden looks blocks
• Sound blocks
  • Standard sound blocks
  • Hidden sound blocks
• Events blocks
  • Standard events blocks
  • Hidden events blocks
• Control blocks
  • Standard control blocks
  • Hidden control blocks
• Sensing blocks
  • Standard sensing blocks
  • Hidden sensing blocks
• Operators blocks
  • Standard operators blocks
  • Hidden operators blocks
• Variables blocks
  • Standard variables blocks
  • Hidden variables blocks
• List blocks
  • Standard list blocks
  • Hidden list blocks
• Custom blocks
  • Standard custom blocks
  • Hidden custom blocks
  • Special custom blocks
• Music blocks
• Pen blocks
• Video Sensing blocks
• Text to Speech blocks
• Translate blocks
• Makey Makey blocks
• micro:bit blocks
• LEGO EV3 blocks
• BOOST blocks
• WeDo 2.0 blocks
• Force and Acceleration blocks
• CoreEx blocks
  • Standard CoreEx blocks
  • Hidden CoreEx blocks

Example block

INFO

This is an example section about a block. It does not exist in Scratch.

The heading for a section about a block should be its opcode, as used in the SB3 file format.

Operation:

A brief overview of the block's function and essential info.

Block:

Arguments:

Name:	Casted to:	Provides the:
ARG	the kind of value this argument is casted to before use by the block, linking to the procedure used to cast it	What it provides to the block.

Procedure:

A deep dive into what the block does in fulfilling its operation.

Motion blocks

These blocks relate to motion, or moving sprites. They manipulate the x position, y position, and direction of a sprite in order to position it in the desired manner. Notably, they do not do anything when used from the stage.

Standard motion blocks

These motion blocks are officially supported in Scratch 3.0:

motion_movesteps

Operation:

Moves the sprite forward the given number of pixels in the direction that it is facing. Negative numbers move the sprite backwards.

Block:

Arguments:

Name:	Casted to:	Provides the:
STEPS	number	Number of steps (aka pixels) to move.

Procedure:

The x position of the sprite is changed by the sine of the sprite's direction multiplied by the number of steps to move, and the y position of the sprite is changed by the cosine of the sprite's direction multiplied by the number of steps to move.

This can be expressed as:

$x^{\prime }=x+\sin (d)\cdot S$

$y^{\prime }=y+\cos (d)\cdot S$

Where $S$ is the STEPS to move, $d$ is the direction of the sprite, and $x$ and $y$ are the x and y positions of the sprite, respectively.

In scratchblocks, this operation can also be replicated as:

After the sprite is moved, its position is fenced.

Hidden motion blocks

These motion blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Looks blocks

These blocks relate to the looks, or appearance of targets. They manipulate the size, costume, layer, visiblility, and graphic effects of a sprite in order to make it appear a certain way.

Standard looks blocks

These looks blocks are officially supported in Scratch 3.0:

TODO

Hidden looks blocks

These looks blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Sound blocks

These blocks relate to sound, or the playback of audio. They play the sound files that a sprite has access to and manipulate the volume and sound effects of a sprite in order to make it stream sounds however is needed.

TODO

Standard sound blocks

These sound blocks are officially supported in Scratch 3.0:

TODO

Hidden sound blocks

These sound blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Events blocks

These blocks relate to the start of a script. They cause scripts to run in order for the project to do things.

Standard events blocks

These events blocks are officially supported in Scratch 3.0:

TODO

Hidden events blocks

These events blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Control blocks

These blocks relate to the execution of other blocks. They cause scripts to run in more complex ways in order for the project to perform more logical operations.

Standard control blocks

These control blocks are officially supported in Scratch 3.0:

TODO

Hidden control blocks

These control blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Sensing blocks

These blocks relate to sensing, or detecting various values. They can read information that couldn't be determined otherwise in order to make the project more aware of its runtime context.

Standard sensing blocks

These sensing blocks are officially supported in Scratch 3.0:

TODO

sensing_username

Operation:

Reports the username of the user that has loaded the project in the context of the Scratch website.

Block:

Arguments:

None

Procedure:

• If the user is signed into their Scratch account (username known):
  • Their username is known, as the user is registered with Scratch and signed into their account.
  • Report the user's username.
• If the user is not signed into their account (username unknown):
  • Their username is not known, as the user is using Scratch without being signed into an account.
  • Report an empty string.

Technically, this block can report any username registered with the Scratch website or the empty string without breaking anything. Although it is meant to report the username of the user who has loaded the project, there is no way for a project to confirm that the reported username is actually theirs.

Hidden sensing blocks

These sensing blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Operators blocks

TODO: Add description

Standard operators blocks

These operators blocks are officially supported in Scratch 3.0:

TODO

Hidden operators blocks

These operators blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Variables blocks

TODO: Add description

Standard variables blocks

These variables blocks are officially supported in Scratch 3.0:

TODO

Hidden variables blocks

These variables blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

List blocks

TODO: Add description

Standard list blocks

These list blocks are officially supported in Scratch 3.0:

TODO

Hidden list blocks

These list blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Custom blocks

TODO: Add description

Standard custom blocks

These custom blocks are officially supported in Scratch 3.0:

TODO

Hidden custom blocks

These custom blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility with projects created in older versions of Scratch or being used internally:

TODO

Special custom blocks

This section may be moved to a relevant appendix, though it will have to be clarified that these blocks can be loaded into Scratch, they just don't do anything outside of mods.

Usually, when a custom block or parameter is used outside of its definition, it does nothing or returns 0. However, there are specific custom blocks and parameters that have unique behaviors when used outside of their definitions, specifically in certain Scratch mods.

A strategy that some Scratch mods use to add their own blocks to Scratch without breaking compatibility (making the project not load in standard Scratch) is by adding them as custom blocks without definitions. In normal Scratch, when a custom block does not have a definition, it won't do anything special; however, when the blocks are run in mods of Scratch, they can be coded to have different behaviors. The behaviors of these blocks in standard Scratch and modifications are specified below:

TODO: Specify!!!

Music blocks

TODO: Add description

TODO: Add sections

Pen blocks

TODO: Add description

TODO: Add sections

Video Sensing blocks

TODO: Add description

TODO: Add sections

Text to Speech blocks

TODO: Add description

TODO: Add sections

Translate blocks

TODO: Add description

TODO: Add sections

Makey Makey blocks

TODO: Add description

TODO: Add sections

micro:bit blocks

TODO: Add description

TODO: Add sections

LEGO EV3 blocks

TODO: Add description

TODO: Add sections

BOOST blocks

TODO: Add description

TODO: Add sections

WeDo 2.0 blocks

TODO: Add description

TODO: Add sections

Force and Acceleration blocks

TODO: Add description

TODO: Add sections

CoreEx blocks

These two extension blocks do not do anything and simply existed with the purpose of testing Scratch 3.0's extension system. They can still be used in projects, though they do not do anything useful and the odds of encountering them in the wild (normal Scratch projects) are highly slim.

Standard CoreEx blocks

There are no standard CoreEx blocks, as they were never intended to be used in projects.

Hidden CoreEx blocks

These CoreEx blocks exist in Scratch 3.0 but are not actively supported or used on their own, either being kept for compatibility reasons or being used internally for testing:

TODO