diff --git a/src/scramble.rs b/src/scramble.rs
index 1ce3cd9..881a96f 100644
--- a/src/scramble.rs
+++ b/src/scramble.rs
@@ -5,7 +5,7 @@ pub fn owen2(n: u32, seed: u32) -> u32 {
     let mut result = n;
 
     for i in 0..32 {
-        let mask = if i < 31 { (!0) << (i + 1) } else { 0 };
+        let mask = (!0 << 1) << i;
         result ^= hash_u32(n & mask, seed) & (1 << i);
     }
 
@@ -25,7 +25,7 @@ pub fn owen2(n: u32, seed: u32) -> u32 {
 /// The implementation below is a full proper base-4 Owen scramble,
 /// requiring only a 24-byte lookup table.
 pub fn owen4(n: u32, seed: u32) -> u32 {
-    const PERM_TABLE: [u8; 24] = [
+    const PERMUTATION_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],
@@ -55,10 +55,11 @@ pub fn owen4(n: u32, seed: u32) -> u32 {
     let mut result = 0;
 
     for i in 0..16 {
-        let mask = if i < 15 { (!0) << ((i + 1) * 2) } else { 0 };
-        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);
+        let mask = (!0 << 2) << (i * 2);
+        let perm_entry = PERMUTATION_TABLE[(hash_u32(n & mask, seed) % 24) as usize];
+        let perm_cell_idx = ((n >> (i * 2)) & 0b11) as usize;
+
+        result |= (((perm_entry >> (perm_cell_idx * 2)) & 0b11) as u32) << (i * 2);
     }
 
     result