add dual-tone letter encoding
add dual-tone letter encoding

chharvey/chharvey.github.io,chharvey/chharvey.github.io,dev-chharvey/dev-chharvey.github.io,chharvey/chharvey.github.io,dev-chharvey/dev-chharvey.github.io,dev-chharvey/dev-chharvey.github.io