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The Cartesian coordinate system The position of sprites on the Stage in the Scratch programming interface is based on a two-dimensional Cartesian coordinate system with the origin at the center of the Stage. The x coordinates range from-240 at the left to +240 at the right. The y coordinates range from +180 at the top to -180 at the bottom.

Three sprites

The area below the stage in Image 4 shows that this program contains two beachballs and one basketball in addition to the Stage. (The beachballs and the basketball are sprites.)

You add a sprite to your program by clicking one of the four buttons immediately below the stage.If you hover your mouse over those buttons going from left to right, the following tooltips appear:

  1. Choose a sprite from library
  2. Paint new sprite
  3. Upload sprite from file
  4. New sprite from camera

In this program, the beachballs and the basketball were added by selecting the first or leftmost button in the row of four buttons and then selecting theappropriate sprite from the library.

Although not visible in the cropped version of the programming interface in Image 4 , when you click on one of the sprites that you have added to the program, thatsprite appears at the top of the rightmost pane. (See Image 6 for example.) Having done that, you can then drag programming blocks into the rightmost pane that define the behavior of thatsprite.

Program code for the LeftBeachball

The code that I wrote (by dragging blocks into the rightmost pane in the programming interface) for the sprite named LeftBeachball is shown in Image 6 . (Note the image of the beachball in the upper right corner. When this is an image of a beachball, all of the scripts in the rightmost panel apply tothat particular beachball sprite.)

Image 6. program code for the left beachball.

Missing image.
Image 6. Program code for the left beachball.

You are already familiar with the tan block with the green flag shown in Image 6 because you learned about it in a previous module. However, theblue block in Image 6 has not been used prior to this module.

Adding the blue go to block to the program

The blue block shown in Image 6 was added to the program module by:

  • Clicking the dark blue button labeled Motion in the upper center of Image 4 .
  • Dragging the blue block shown in Image 6 from the toolbox to therightmost panel and clicking it into place under the tan block.
  • Typing the literal values -200 and 0 into the two white boxes on the blue block.

Coordinate values

If you move the mouse pointer around the stage in the programming interface, the coordinates of the mouse pointer are displayed immediately below the stage as shown in Image 4 . As mentioned earlier, the xcoordinates range from -240 at the left to +240 at the right. The y coordinates range from +180 at the top to -180 at the bottom.

Behavior of the LeftBeachball

The behavior of the script shown in Image 6 can be interpreted as follows: When the user clicks the green flag, cause the sprite named LeftBeachball to move to a location with an x (horizontal) coordinate value of -200 and a y (vertical) coordinate value of 0. Since the origin is at the center of the Stage, this causes the beachball to move to theleft of the origin on the horizontal axis.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Teaching beginners to code. OpenStax CNX. May 27, 2013 Download for free at http://cnx.org/content/col11498/1.20
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