boolean colored() {
        return type == Compiler.PLAIN || type == Compiler.AHEAD || type == Compiler.BEHIND;
    }
boolean colored() {
        return type == Compiler.PLAIN || type == Compiler.AHEAD || type == Compiler.BEHIND;
    }
boolean colored ( ) { return type == Compiler . PLAIN || type == Compiler . AHEAD || type == Compiler . BEHIND ; }
is an arc colored, and hence on a color chain?
is an arc colored and hence on a color chain?