     }
     
     public var description: String {
-        return h.map{ $0.description }.joined(separator: "\t->\t")
-            + "\n--------------------\n"
-            + degrees.map { n -> String in
-                "\(n): \t" + (0 ..< 3).map { i in
-                    let k = self.seqIndex(i, n)
-                    return "\(sequence.objectDescription(k))\t\(sequence.arrowDescription(k))\t"
+        let title = h.map{ h in h.description }.joined(separator: " -> ")
+        let head = "n\\i\t" + h.enumerated().map{ (i, _) in "\(i)" }.joined(separator: "\t\t")
+        let lines = degrees.map { n -> String in
+            "\(n)\t" + (0 ..< 3).map { i in
+                let k = self.seqIndex(n, i)
+                return "\(sequence.objectDescription(k))\t\(sequence.arrowDescription(k))\t"
                 }.joined()
-              }.joined(separator: "\n")
-            + "0"
-    }
-    
-    public var detailDescription: String {
-        func s(_ i: Int, _ n: Int) -> String {
-            return self[i, n].map{ "\($0)" } ?? "?"
         }
-        return "\(self.description)\n--------------------\n"
-            + degrees.map { n -> String in
-                "\(n): \t" + (0 ..< 3).map{ i in self[i, n].map{ "\($0)" } ?? "?" }.joined(separator: "\t-> ")
-                }.joined(separator: "\t->\n")
-            + "\t-> 0"
+        return ([title, head] + lines).joined(separator: "\n")
     }
 }

        return sequence.solve()
    }
    
    public func assertExactness(column i: Int, degree n: Int) {
        let k = seqIndex(i, n)
        sequence.assertExactness(at: k)
    }
    

        return (topDegree - bottomDegree + 1) * 3
    }
    
    internal func seqIndex(_ n: Int, _ i: Int) -> Int {
        return T.descending ? (topDegree - n) * 3 + i : (n - bottomDegree) * 3 + i
    }
    
    internal func gridIndex(_ k: Int) -> (Int, Int) {
        let (i, j) = (k >= 0) ? (k % 3, k / 3) : (k % 3 + 3, k / 3 - 1)
        return (T.descending ? topDegree - j : bottomDegree + j, i)
    }
    
    internal var degrees: [Int] {
