Update app.py

app.py

@@ -228,6 +228,34 @@ def longest_cib(d: int):
     return seq
 
 
+def shorter_cib(d: int):
+    """
+    Return a predefined coil/snake for certain dimensions,
+    otherwise fall back to a standard Gray-code path.
+    """
+    presets = {
+        2: [0, 1, 3, 2, 0],
+        3: [0, 1, 3, 7, 6, 4, 0],
+        4: [0, 1, 3, 7, 6, 4, 0],
+        5: [0, 1, 3, 7, 6, 14, 12, 13, 29, 21, 20, 16, 0],
+        6: [0, 1, 3, 7, 15, 31, 29, 25, 24, 26, 10, 42, 43, 59, 51, 49, 53, 37, 45, 44, 60, 62, 54, 22, 20, 4, 0],
+        7: [0, 1, 3, 7, 15, 13, 12, 28, 30, 26, 27, 25, 57, 56, 40, 104, 72, 73, 75, 107, 111, 110, 46, 38, 36, 52,116, 124, 125, 93, 95, 87, 119, 55, 51, 50, 114, 98, 66, 70, 68, 69, 101, 97, 113, 81, 80, 16, 0],
+        8: [0, 1, 3, 7, 6, 14, 12, 13, 29, 31, 27, 26, 18, 50, 54, 62, 60, 56, 57, 49, 53, 37, 101, 69, 68, 196, 132, 133, 149, 151, 150, 158, 156, 220, 92, 94, 86, 87, 119, 115, 123, 122, 250, 254, 255, 191, 187, 179, 163, 167, 231, 230, 226, 98, 66, 74, 202, 200, 136, 137, 139, 143, 207, 205, 237, 173, 172, 174, 170, 42, 43, 47, 111, 110, 108, 104, 105, 73, 89, 217, 219, 211, 195, 193, 225, 241, 245, 244, 116, 112, 80, 208, 144, 176, 160, 32, 0],
+    }
+
+    if d in presets:
+        return presets[d][:]  # copy, so we don't mutate the original
+        
+    return [0]
+    # Fallback: Gray-code Hamiltonian path for other dimensions
+    n = 1 << d
+    seq = []
+    for i in range(n):
+        g = i ^ (i >> 1)
+        seq.append(g)
+    return seq
+
+
 
 def parse_path(text: str, d: int) -> List[int]:
     if not text:
@@ -484,7 +512,7 @@ app.layout = html.Div(
                 html.Button("Longest CIB", id="btn_longest_cib", n_clicks=0,
                             style={"background": "#059669", "color": "white"}),
                 html.Button("Shorter CIB", id="btn_shorter_cib", n_clicks=0,
-                            style={"background": "#FFFF00", "color": "white"}),
+                            style={"background": "#FFFF00"}),
                 html.Button("Clear", id="btn_clear", n_clicks=0),
             ]
         ),
@@ -573,6 +601,7 @@ def stats(d, path):
     Input("fig", "clickData"),
     Input("btn_clear", "n_clicks"),
     Input("btn_longest_cib", "n_clicks"),
+    Input("btn_shorter_cib", "n_clicks"),
     Input("btn_set", "n_clicks"),
     Input("btn_swap", "n_clicks"),
     Input("btn_flip", "n_clicks"),
@@ -605,10 +634,14 @@ def update_path(clickData,
     if trigger == "btn_clear":
         return []
 
-    # 2) Longest CIB
+    # 2a) Longest CIB
     if trigger == "btn_longest_cib":
         return longest_cib(d)
 
+    # 2b) Shorter CIB
+    if trigger == "btn_longest_cib":
+        return shorter_cib(d)
+
     # 3) Manual set path
     if trigger == "btn_set":
         newp = parse_path(manual_text or "", d)