diff --git a/src/dims.py b/src/dims.py
index 0eac11b..d1b5d80 100644
--- a/src/dims.py
+++ b/src/dims.py
@@ -3,3 +3,4 @@ DIMS_8 = (2, 3, 5, 7, 11, 13, 17, 19)
 DIMS_7 = (2, 3, 5, 7, 11, 13, 17)
 DIMS_5 = (2, 3, 5, 7, 11)
 DIMS_4 = (2, 3, 5, 7)
+DIMS_3 = (2, 3, 5)
diff --git a/src/io.py b/src/io.py
index 25d57d5..ece8216 100644
--- a/src/io.py
+++ b/src/io.py
@@ -325,7 +325,7 @@ def save_graph_to_cache(
 def main():
     """Demo: Generate compact sets and build graph."""
     import argparse
-    from .dims import DIMS_4, DIMS_5, DIMS_7, DIMS_8
+    from .dims import DIMS_3, DIMS_4, DIMS_5, DIMS_7, DIMS_8
     from .harmonic_space import HarmonicSpace
     from .pathfinder import PathFinder
 
@@ -414,7 +414,10 @@ def main():
         help="Make symdiff selection uniform across range (ignore weight differences)",
     )
     parser.add_argument(
-        "--dims", type=int, default=7, help="Number of prime dimensions (4, 5, 7, or 8)"
+        "--dims",
+        type=int,
+        default=7,
+        help="Number of prime dimensions (3, 4, 5, 7, or 8)",
     )
     parser.add_argument("--chord-size", type=int, default=3, help="Size of chords")
     parser.add_argument("--max-path", type=int, default=50, help="Maximum path length")
@@ -530,7 +533,9 @@ def main():
         return  # Exit after OSC playback
 
     # Select dims
-    if args.dims == 4:
+    if args.dims == 3:
+        dims = DIMS_3
+    elif args.dims == 4:
         dims = DIMS_4
     elif args.dims == 5:
         dims = DIMS_5
diff --git a/src/transcriber.py b/src/transcriber.py
index 432943e..e6d9e8e 100644
--- a/src/transcriber.py
+++ b/src/transcriber.py
@@ -347,8 +347,8 @@ def _is_adjacent(hs1: tuple, hs2: tuple) -> bool:
 
 def _compute_dim_diff(current: tuple, prev: tuple) -> int:
     """Compute dim_diff between two hs_arrays. Returns prime * direction."""
-    primes = [3, 5, 7]
-    for i in range(1, 4):
+    primes = [3, 5, 7, 11]
+    for i in range(1, 5):
         diff = current[i] - prev[i]
         if diff == 1:
             return primes[i - 1]