  Many people with severely limited muscle control can only communicate through
augmentative and alternative communication (AAC) systems with a small number of
buttons. In this paper, we present the design for ColorCode, which is an AAC
system with two buttons that uses Bayesian inference to determine what the user
wishes to communicate. Our information-theoretic analysis of ColorCode
simulations shows that it is efficient in extracting information from the user,
even in the presence of errors, achieving nearly optimal error correction.
ColorCode is provided as open source software
(https://github.com/mrdaly/ColorCode).
