fourmilab / mind_grenade

Emulator of the 1969 Mind Grenade hardware random music generator for Second Life in Linden Scripting Language

Fourmilab Mind Grenade

Fourmilab Mind Grenade is a model of the Mind Grenade random music generator for the Second Life virtual world.

The Mind Grenade uses a linear-feedback shift register to generate pseudorandom music which is played at a given tempo (notes per second). The shift register is 31 bits in length, which provides a sequence of sufficient length that with the default tempo of four notes per second the tune will not repeat for over 17 years. Nine lights show the state of the least significant bits of the shift register (the original hardware Mind Grenade used a 9-bit register) and can display in either colour (based on a three bit history for each cell in the shift register) or monochrome (showing only the current state of each bit).

This repository contains all of the software and resources, including programs in Linden Scripting Language, sound clips, notecards, and development documentation, tools, and resources used the model and its development. The actual model is built within Second Life and these components are installed within it.

The complete model is available for free in the Second Life Marketplace. This repository contains everything in the model (except the prims, which are objects built within Second Life), plus additional resources for developers who may wish to extend or adapt the model as they wish. The model is delivered with "full permissions": those who obtain it are free to copy, modify, and transfer it to other users within Second Life.

All of this software is licensed under the Creative Commons Attribution-ShareAlike license. Please see LICENSE.md in this repository for details.