memberp --Operation (predicate), two inputs.
     If the second input is a word, the first input must be a word of
     length one (a single character), and the output is true if and only if
     the first input is contained in the second as a character. If the
     second input is a list, the first input can be any Logo object, and
     the output is true if and only if the first input is a member of the
     second input. (Note that this is member, not subset.)