(overlap '(a b a c) '(a b a c))

(overlap '(a b a c) '(a a b a b a c a c a b a c d e g a b a b a c a c))

(overlap '(a a a b) '(c c c c a a b a a a a a a a b a a a a a a a b a a))

(overlap '(a b r a c a d a b r a) '(a b r a b r a c a d a b r a c a b r a c a))

(overlap '(a b r a c a d a b r a) '(a b r a b r a c a d a b r a c a d a b r a c a d a b r a c a b r a c a))

(overlap '(a b a c d a b a c e) '(a b a b a c d a b a c d a b a c e g g))

(overlap '(a a a) '(a a a a a a ))