diff --git a/0004-adt/Algebraic Data Types.playground/Contents.swift b/0004-algebraic-data-types/Algebraic Data Types.playground/Contents.swift
similarity index 100%
rename from 0004-adt/Algebraic Data Types.playground/Contents.swift
rename to 0004-algebraic-data-types/Algebraic Data Types.playground/Contents.swift
diff --git a/0004-adt/Algebraic Data Types.playground/contents.xcplayground b/0004-algebraic-data-types/Algebraic Data Types.playground/contents.xcplayground
similarity index 100%
rename from 0004-adt/Algebraic Data Types.playground/contents.xcplayground
rename to 0004-algebraic-data-types/Algebraic Data Types.playground/contents.xcplayground