cLogos is an implementation of the Berkeley Logo language written in Common Lisp, designed to be a faithful and living environment for computational thinking. It aims to bridge textual symbolic reasoning with spatial turtle geometry by treating them as coexisting modes of thought rather than distinct stages. The project prioritizes structural honesty, pedagogical transparency, and deep inspectability within the host programming language's environment.
- Maintains compatibility with canonical Berkeley Logo specifications
- Bridges procedural/temporal logic with algebraic/relational structures
- Emphasizes high levels of inspectability from Common Lisp
- Uses ASDF for explicit dependency management and structural honesty
This video features Professor Marvin Minsky demonstrating the 2500 computer, a system he designed to provide powerful, accessible graphics and animation for schools at a low cost (approx. $5,000) (1:36 - 4:06).
Key features and concepts discussed include:
Hardware Design: The 2500 is a vector-based system using about 250 chips, capable of drawing lines, curves, and points rapidly. It is optimized for line drawings rather than filled-in, shaded regions (2:32 - 3:34).
Storage and Bandwidth: Programs can be saved on standard audio cassettes, and because the system stores coordinate lists rather than full video frames, it is highly efficient and can even transmit images over standard telephone lines (5:45 - 6:50).
Turtle Geometry: Professor Seymour Papert introduces Logo, a programming language designed to make animation and graphics intuitive for children and non-programmers. By using simple commands like 'forward', 'right', and 'spin', users can create complex geometric shapes and patterns without needing advanced mathematics (7:42 - 13:00).
Performance and Artifacts: The creators discuss the display's performance, noting its capability to handle 1,500 vectors at 60 frames per second, and address potential visual artifacts such as flickering or line overlap (14:20 - 16:50).
Artistic Potential: The team emphasizes that while their current demonstrations have been primarily geometric, the system holds potential for artists to create complex, aesthetically pleasing imagery if given the time and skill (18:13 - 19:15).
The source code for the Apple II version of the LOGO programming language has been found! This is a significant discovery for computer history enthusiasts and those interested in the early days of programming education. The code was found on an old floppy disk and has been preserved and made available online.