Logo

Logo, short for Logo Programming Language, was created in 1967 by Wally Feurzeig, Seymour Papert, and Cynthia Solomon at Bolt, Beranek and Newman. Logo is an educational programming language designed to teach programming concepts, problem-solving, and computational thinking. It is widely used in schools and educational software to introduce children to coding, mathematics, and algorithmic thinking. Developers can access Logo by downloading implementations such as MIT Logo, which provides the interpreter, documentation, and cross-platform support for Windows, macOS, and Linux.

Logo exists to make programming approachable and intuitive, particularly for learners and students. Its design philosophy emphasizes simplicity, readability, and visual feedback. By combining textual commands with graphical outputs such as turtle graphics, Logo solves the problem of abstract programming concepts being difficult to grasp, enabling learners to see immediate results of code execution and understand computational processes.

Logo: Turtle Graphics

Logo is best known for its turtle graphics system, where commands control a “turtle” that moves on the screen to draw shapes and patterns. This system provides visual reinforcement of programming concepts.

; Logo turtle graphics example
FORWARD 100
RIGHT 90
FORWARD 100
RIGHT 90
FORWARD 100
RIGHT 90
FORWARD 100

The turtle follows sequential commands to move and turn, drawing lines that form shapes. This visual, immediate feedback makes learning programming concepts intuitive, similar to interactive environments in Scratch and Python with turtle libraries.

Logo: Procedures and Variables

Logo supports procedures (functions) and variables, allowing learners to create reusable code blocks and store values for computation.

; Define a procedure to draw a square
TO SQUARE :SIZE
  REPEAT 4 [FORWARD :SIZE RIGHT 90]
END

; Call the procedure
SQUARE 100

Procedures encapsulate instructions, and variables store data such as distances or angles. This structured approach introduces learners to modular programming, conceptually similar to Python functions and Smalltalk message blocks.

Logo: Recursion and Loops

Logo supports recursion and looping constructs, allowing learners to define iterative or self-referential behavior for more complex patterns.

; Recursive procedure to draw nested squares
TO NESTEDSQUARE :SIZE :COUNT
  IF :COUNT = 0 [STOP]
  REPEAT 4 [FORWARD :SIZE RIGHT 90]
  NESTEDSQUARE :SIZE/2 :COUNT-1
END

; Call the recursive procedure
NESTEDSQUARE 200 4

Recursion and loops help visualize algorithmic thinking and repetitive patterns. Learners can observe outcomes directly, similar to recursion in Python or iterative constructs in Smalltalk.

Logo: Lists and Data Structures

Logo includes basic list structures for storing sequences of values, enabling computation over collections of data.

; Working with lists in Logo
MAKE "numbers [1 2 3 4 5]
PRINT FIRST :numbers
PRINT LAST :numbers
PRINT BUTFIRST :numbers

Lists provide storage and access for sequences of values, supporting algorithmic exploration and data manipulation. This is conceptually similar to lists in Python and arrays in Smalltalk.

Logo is used in educational settings to teach programming, mathematics, and problem-solving. Its turtle graphics, procedures, recursion, and list handling provide hands-on experience with fundamental programming concepts. When used alongside Scratch, Python, and Smalltalk, Logo enables learners to build computational thinking, algorithmic skills, and visual programming understanding in a safe and interactive environment.