diff --git a/bhv/abstract.py b/bhv/abstract.py
index 6292317..71f92b8 100644
--- a/bhv/abstract.py
+++ b/bhv/abstract.py
@@ -90,17 +90,37 @@ def hamming(self, other: Self) -> int:
         return (self ^ other).active()
 
     def closest(self, vs: list[Self]) -> int:
+        """Return index of the vector that is closest in hamming distance to self"""
         return min(range(len(vs)), key=lambda i: self.hamming(vs[i]))
 
+    def furthest(self, vs: list[Self]) -> int:
+        """Return index of the vector that is furthest in hamming distance to self"""
+        return max(range(len(vs)), key=lambda i: self.hamming(vs[i]))
+
     def top(self, vs: list[Self], k: int) -> list[int]:
+        """Return the indices of the k vectors that have the smallest hamming distance from self"""
         return list(sorted(range(len(vs)), key=lambda i: self.hamming(vs[i])))[:k]
 
+    def bottom(self, vs: list[Self], k: int) -> list[int]:
+        """Return the indices of the k vectors that have the biggest hamming distance from self"""
+        return list(sorted(range(len(vs)), key=lambda i: self.hamming(vs[i])))[(len(vs) - k):]
+
     def within(self, vs: list[Self], d: int) -> list[int]:
+        """Return the indices of all the vectors with maximum hamming distance d to self (including distance d)"""
         return list(filter(lambda i: self.hamming(vs[i]) <= d, range(len(vs))))
 
+    def outside(self, vs: list[Self], d: int) -> list[int]:
+        """Return the indices of all the vectors with minimum hamming distance d to self (excluding distance d)"""
+        return list(filter(lambda i: self.hamming(vs[i]) > d, range(len(vs))))
+
     def within_std(self, vs: list[Self], d: float, relative: bool = False) -> list[int]:
+        """Return the indices of all vectors that are less than d standard deviations away from self (including d)"""
         return self.within(vs, int(DIMENSION*(self.std_to_frac(d + self.EXPECTED_RAND_APART*relative))))
 
+    def outside_std(self, vs: list[Self], d: float, relative: bool = False) -> list[int]:
+        """Return the indices of all vectors that are more than d standard deviations away from self (including d)"""
+        return self.outside(vs, int(DIMENSION*(self.std_to_frac(d + self.EXPECTED_RAND_APART*relative))))
+
     def distribution(self, vs: list[Self], metric=lambda x, y: x.std_apart(y), softmax: bool = False, base: int = e):
         ds = [metric(self, v) for v in vs]
         if softmax:
diff --git a/tests/abstract.py b/tests/abstract.py
new file mode 100644
index 0000000..24934b4
--- /dev/null
+++ b/tests/abstract.py
@@ -0,0 +1,58 @@
+import unittest
+
+from bhv.vanilla import VanillaBHV as BHV, DIMENSION
+
+
+class BaseBHVMethods(unittest.TestCase):
+    def test_closest_furthest(self):
+        a, b, c, d = BHV.nrand(4)
+
+        self.assertEqual(0, a.closest([a, b, c, d]))
+
+        self.assertEqual(1, a.furthest([a, b]))
+        self.assertEqual(1, a.furthest([BHV.majority([a, b, c]), BHV.majority([a, b, c, d])]))
+
+    def test_top_bottom(self):
+        a, b, c, d = BHV.nrand(4)
+
+        self.assertEqual([0, 1], a.top([a, BHV.majority([a, b, c]), BHV.majority([a, b, c, d])], 2))
+        self.assertEqual([1, 2], a.bottom([a, BHV.majority([a, b, c]), BHV.majority([a, b, c, d])], 2))
+
+    def test_within_outside(self):
+        a, b, c, d = BHV.nrand(4)
+
+        self.assertEqual([0], a.within([a, b], 0))
+        self.assertEqual([0, 1], a.within([a, b], DIMENSION))
+        self.assertEqual([0], a.within([a ^ BHV.level(1)], DIMENSION))
+        self.assertEqual([], a.within([a ^ BHV.level(1)], DIMENSION - 1))
+        self.assertEqual([], a.within([a ^ BHV.level(.5)], DIMENSION/2 - 1))
+        self.assertEqual([0], a.within([a ^ BHV.level(.5)], DIMENSION/2))
+        self.assertEqual([0, 1], a.within([a, a ^ BHV.level(.001), a ^ BHV.level(.1), b], 100))
+
+        self.assertEqual([], a.outside([a], 0))
+        self.assertEqual([], a.outside([b], DIMENSION))
+        self.assertEqual([], a.outside([a ^ BHV.level(1)], DIMENSION))
+        self.assertEqual([0], a.outside([a ^ BHV.level(1)], DIMENSION - 1))
+        self.assertEqual([0], a.outside([a ^ BHV.level(.5)], DIMENSION / 2 - 1))
+        self.assertEqual([], a.outside([a ^ BHV.level(.5)], DIMENSION / 2))
+        self.assertEqual([2, 3], a.outside([a, a ^ BHV.level(.001), a ^ BHV.level(.1), b], 100))
+
+        vs = BHV.nrand(20)
+        for w in vs:
+            for a in range(0, DIMENSION, round(DIMENSION/100)):
+                self.assertSetEqual(set(w.outside(vs, a)), set(range(len(vs))) - set(w.within(vs, a)))
+
+    def test_within_outside_std(self):
+        a, b, c, d = BHV.nrand(4)
+
+        self.assertEqual([0, 1], a.within_std([a, b], a.std_apart(b)))
+        self.assertEqual([], a.outside_std([a, b], a.std_apart(b)))
+
+        vs = BHV.nrand(20)
+        for w in vs:
+            for a in range(100):
+                self.assertSetEqual(set(w.outside_std(vs, a)), set(range(len(vs))) - set(w.within_std(vs, a)))
+
+
+if __name__ == '__main__':
+    unittest.main()