First Forward into Logo 1: Square Five

1532 /www/nrich/html/content/99/07/logo1/ 1 2011-02-01T00:00:01 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><a href="https://nrich.maths.org/8045">First Forward Into Logo</a> This is the first in a twelve part series of articles introducing Logo programming for beginners. Even if you have never tried LOGO it is easy to learn and here is the place to get started! The programs in this article were written using MSWLogo and you can download this excellent free software from the internet at <a href="http://fmslogo.sourceforge.net/">http://fmslogo.sourceforge.net/</a>. With only a limited set of instructions (i.e. primitives) it is usually quite straightforward to draw the most complex of shapes on the screen or to get the `turtle' to manoeuvre about the floor. For example, using instructions such as: <pre> <code>forward 40 (FD 40) or backward 20 (BK 20), right 85 (RT 85 ) or left 125 (LT 125)</code> </pre> The difficulty always seems to be about remembering to put spaces between the commands - FD, BK, RT, or LT and the amount of distance or turning you want the screen or floor turtle to achieve: <table> <tbody> <tr> <td> <pre> <code>e.g. FD 70 RT 90 FD 130 RT 90 FD 70 RT 90 FD 130 RT 90 </code> </pre></td> <td><mdo:image src="animation.gif"></mdo:image></td> </tr> </tbody> </table> <div>And, there is the convention of returning the screen or floor turtle to exactly the same place that it had started from.</div> <div>The NRICH site has a number of LOGO Challenges for you to think about and respond to. In many cases you will know how well you are doing by how quickly you manage to copy the drawing exactly, in others the aim is for you to investigate the code you have been given and discover what is going on.</div> <div>When you work at the problems it would be helpful to keep a simple diary of what you were thinking at the time and what you learnt while trying to respond to the challenges set. What mathematics did you learn along the way? Are you getting better at learning things independently? What did you learn about yourself?</div> <div>e.g.</div> <ul> <li>How impatient did you become?</li> <li>How did you get round the difficulties you met?</li> <li>Did you share what you did with others?</li> <li>Did other people help you solve the challenge? In what ways?</li> <li>What happened when the instructions you had worked out did not draw the shape required?</li> </ul> <h5>The first LOGO Challenge</h5> For now, a reminder of some of the PRIMITIVES (the commands) needed to start drawing: <pre> <code>FD forward BK backward LT left RT right PU pen up PD pen down HT hide turtle ST show turtle CS clear screen CT clear text </code> Now FD to the first challenge... </pre> <hr></hr> <mdo:image align="left" alt="" src="square-5.gif"></mdo:image> Can you use LOGO to draw the 5-square? Next: <a href="http://nrich.maths.org/4852">FF2</a> </mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"> Most of the Logo challenges do not have solutions because you will know that your program is correct if it draws the required shapes. In addition you could write different programs and still get the desired result. In this case we give below a very simple program. It has has many repetitions and it could be made shorter and more elegant by using a REPEAT command which will be introduced in the next section. Here we give just a list of commands but we shall learn to give each short program its own name and to use that name as a command to start the program. Note that the program is written here in small case letters rather than capitals and most LOGO software allows either. It is good practice to be consistent and stick to one or the other and we generally use capitals because they are easier to read. rt 45 fd 20 lt 90 fd 40 rt 90 fd 40 lt 90 fd 40 rt 90 fd 20 rt 90 fd 20 rt 90 fd 40 lt 90 fd 40 rt 90 fd 40 lt 90 fd 20 lt 90 fd 80 lt 90 fd 80 lt 90 fd 80 lt 90 fd 80 lt 135 </mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"> Think of the overall picture as being made of: a single length and turns of 45 degrees or 90 degrees or one large square and smaller squares, the lengths of whose sides you need to choose or small squares (you can draw one square, and the next, and the next, but where do you start each time?) and then the large square. How about having a base length of 20 and start by turning through 45 degrees, something like: RT 45 FD 20 FD 20 FD 20 FD 20 LT 90 ... What am I drawing? </mdoxml> 2 3 0 1 1 1 0 First Forward into Logo 1: Square Five A Short introduction to using Logo. This is the first in a twelve part series. Information and Communications Technology Logo 2D Geometry, Shape and Space Squares Sequences, Functions and Graphs Iteration Information and Communications Technology Programming Applications STEM - General