all$ = "1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1"

FOR word$ IN all$
    FOR x = LEN(word$)/2 DOWNTO 1

        ex$ = EXPLODE$(word$, x)

        FOR st$ IN UNIQ$(ex$)
            IF NOT(REGEX(HEAD$(ex$, 1), "^" & st$)) THEN CONTINUE 2
        NEXT

        PRINT "Repeating string: ", word$, " -> ", HEAD$(ex$, 1)
        CONTINUE 2
    NEXT

    PRINT "Not a repeating string: ", word$
NEXT