LOGO Challenge - Blob
Working with recursion. What is going on how does each iteration
feen into the next? All within a geometric setting.
Age
14 to 18
Challenge level
Problem
Think carefully about the procedure below.
This procedure looks at the technique called recursion and can be used to build up a particularly pleasing catalogue of patterns that spiral!
Investigate this intriguing procedure, try to formulate some ideas about what is happening and test any conjectures that arise.
TO BLOB :A :C
FD 5 RT :A
WAIT 10
BLOB :A + :C :C
END
You will have to tell LOGO to "HALT" at some point otherwise this will go on forever - why?
Try: BLOB 3 9 / BLOB 2 8 and go from there.
BLOB 1 10 and BLOB 11 18 are reproduced here for you...
Image
Teachers' Resources
You might like to make the number after theWAIT command larger so that you have time to see what is happening. Alternatively, many LOGO programmes allow you to "Step" through a procedure and see the results of each line of code.
There are two variables - try fixing one and varying the other.
It might also be helpful to imagine the variable as a box into which you put a number and to record on a piece of paper the number in the variable boxes after each iteration of the procedure.