1. "Turtle Graphics“ for kids.
LOGO
"Turtle Graphics“ for kids.
Ask if anyone has ever used LOGO before.
Ask if anyone has ever heard of LOGO.

2. History Logo: from Greek logos for “word”
Developed by a team at MIT in 1960s
Notable: Seymour Papert
Mathematician from Geneva
Worked with Piaget who influenced him
Designed as a dialect of LISP

3. Why the Turtle? Originally a robotic creature sat on floor
Domed shape with shell-like electronics casing
Slow movement of device
Directed to move around and draw by typing commands at computer
Designed to be programmed by children
Less expensive version created on computer

4. Evolution 130 existing implementations
Driven by commercial and regional factors
1977
1985
1993
1967
2003
Object Logo
IBM Logo
MacLogo
Logo Learner
LEGO LOGO
LEGO LOGO
PC LOGO
WIN LOGO
Comenius Logo
TILOGO
Apple LOGO
Atari Logo
LOGO Writer
Logo Grafico
MicroWorlds LOGO
Mach Turtles Logo
UCB Logo
MSWLogo

5. Language Concepts Basic commands Control Structures
while condition [instruction list]
until condition [instruction list ]
repeat number [instruction list]
Recursion (preferred paradigm)
Scoping
Global variables: if not declared before use
Local variables:
may be declared
Input variables for functions are local

6. Basic commands
Forward 100 (FD 100) - moves the turtle forward 100 units
Back 50 (BK 50) - moves the turtle back 50 units
Right 45 (RT 45) - turns the turtle 45 degrees to the right
Left 90 (LT 90) - turns the turtle 90 degrees to the left
Home - Returns the turtle to its origin
ClearSceen (CS) - Erases the screen

7. Features Graphics / Music Extensibles: basic operations “primitives.”
Working Definitions: allows for user-defined new definitions
Modularity
Interactivity
Flexibility

8. Recursion to spiral :size
if :size > 30 [stop] ; a condition stop fd :size rt ; many lines of action spiral :size * ; the tailend recursive call
end

9. MSW LOGO Implemenation
Source:

10. Example: Square Turtle Moves forward and turns 90º 4 times
REPEAT 4 [FD 100 RT 90]
Source:

11. Examples
Source:

12. Future of Logo New Releases of LOGO: NetLogo StarLogo
Parallel modeling and simulation
Northwestern University
StarLogo
MIT