diff --git a/src/scramble.rs b/src/scramble.rs
index e7d6af6..cc3b5c1 100644
--- a/src/scramble.rs
+++ b/src/scramble.rs
@@ -17,41 +17,41 @@ pub fn owen(n: u32, seed: u32) -> u32 {
 /// of Pixels" by Ahmed et al., except using a more complete and
 /// efficient algorithm based on the Owen scrambling function above.
 pub fn z_scramble(n: u32, seed: u32) -> u32 {
+    const PERM_TABLE: [u8; 24] = [
+        0 | (1 << 2) | (2 << 4) | (3 << 6), // [0, 1, 2, 3],
+        0 | (1 << 2) | (3 << 4) | (2 << 6), // [0, 1, 3, 2],
+        0 | (2 << 2) | (1 << 4) | (3 << 6), // [0, 2, 1, 3],
+        0 | (2 << 2) | (3 << 4) | (1 << 6), // [0, 2, 3, 1],
+        0 | (3 << 2) | (1 << 4) | (2 << 6), // [0, 3, 1, 2],
+        0 | (3 << 2) | (2 << 4) | (1 << 6), // [0, 3, 2, 1],
+        1 | (0 << 2) | (2 << 4) | (3 << 6), // [1, 0, 2, 3],
+        1 | (0 << 2) | (3 << 4) | (2 << 6), // [1, 0, 3, 2],
+        1 | (2 << 2) | (0 << 4) | (3 << 6), // [1, 2, 0, 3],
+        1 | (2 << 2) | (3 << 4) | (0 << 6), // [1, 2, 3, 0],
+        1 | (3 << 2) | (0 << 4) | (2 << 6), // [1, 3, 0, 2],
+        1 | (3 << 2) | (2 << 4) | (0 << 6), // [1, 3, 2, 0],
+        2 | (0 << 2) | (1 << 4) | (3 << 6), // [2, 0, 1, 3],
+        2 | (0 << 2) | (3 << 4) | (1 << 6), // [2, 0, 3, 1],
+        2 | (1 << 2) | (0 << 4) | (3 << 6), // [2, 1, 0, 3],
+        2 | (1 << 2) | (3 << 4) | (0 << 6), // [2, 1, 3, 0],
+        2 | (3 << 2) | (0 << 4) | (1 << 6), // [2, 3, 0, 1],
+        2 | (3 << 2) | (1 << 4) | (0 << 6), // [2, 3, 1, 0],
+        3 | (0 << 2) | (1 << 4) | (2 << 6), // [3, 0, 1, 2],
+        3 | (0 << 2) | (2 << 4) | (1 << 6), // [3, 0, 2, 1],
+        3 | (1 << 2) | (0 << 4) | (2 << 6), // [3, 1, 0, 2],
+        3 | (1 << 2) | (2 << 4) | (0 << 6), // [3, 1, 2, 0],
+        3 | (2 << 2) | (0 << 4) | (1 << 6), // [3, 2, 0, 1],
+        3 | (2 << 2) | (1 << 4) | (0 << 6), // [3, 2, 1, 0],
+    ];
+
     let mut result = 0;
 
     for i in 0..16 {
         let mask = if i < 15 { (!0) << ((i + 1) * 2) } else { 0 };
-        let entry = (hash_u32(n & mask, seed) % 24) as usize;
-        let cell = ((n >> (i * 2)) & 0b11) as usize;
-        result |= (Z_TABLE[entry][cell] as u32) << (i * 2);
+        let perm_entry = PERM_TABLE[(hash_u32(n & mask, seed) % 24) as usize];
+        let perm_cell_i = ((n >> (i * 2)) & 0b11) as usize;
+        result |= (((perm_entry >> (perm_cell_i * 2)) & 0b11) as u32) << (i * 2);
     }
 
     result
 }
-
-const Z_TABLE: &[[u8; 4]; 24] = &[
-    [0, 1, 2, 3],
-    [0, 1, 3, 2],
-    [0, 2, 1, 3],
-    [0, 2, 3, 1],
-    [0, 3, 1, 2],
-    [0, 3, 2, 1],
-    [1, 0, 2, 3],
-    [1, 0, 3, 2],
-    [1, 2, 0, 3],
-    [1, 2, 3, 0],
-    [1, 3, 0, 2],
-    [1, 3, 2, 0],
-    [2, 0, 1, 3],
-    [2, 0, 3, 1],
-    [2, 1, 0, 3],
-    [2, 1, 3, 0],
-    [2, 3, 0, 1],
-    [2, 3, 1, 0],
-    [3, 0, 1, 2],
-    [3, 0, 2, 1],
-    [3, 1, 0, 2],
-    [3, 1, 2, 0],
-    [3, 2, 0, 1],
-    [3, 2, 1, 0],
-];