1 files changed, 17 insertions, 7 deletions

diff --git a/src/hitomezashi.rs b/src/hitomezashi.rs
index 24a59be..88ba387 100644
--- a/src/hitomezashi.rs
+++ b/src/hitomezashi.rs
@@ -47,6 +47,12 @@ pub fn hitomezashi(width: usize, height: usize, skew: Option<f64>) {
 		col_bits.push(brn.sample(&mut rng));
 	}
 
+	let mut alt_bits: Vec<bool> = Vec::with_capacity(width - 1);
+
+	for col in 0..width {
+		alt_bits.push(col % 2 == 1);
+	}
+
 	// each new row of the pattern depends on the bits directly above it
 	let mut above_bits: Vec<bool> = Vec::with_capacity(width);
 
@@ -65,13 +71,17 @@ pub fn hitomezashi(width: usize, height: usize, skew: Option<f64>) {
 
 	// height-1 because the first row has already been printed
 	for row in 0..(height - 1) {
-		for col in 0..width {
-			/* each square in each successive row is derived from the square above it. the row bits
-			 * represent whether there's a stitch between the two squares. if there's a stitch, the
-			 * squares are different, otherwise they are the same. */
-			above_bits[col] = above_bits[col] ^ (row_bits[row] ^ (col % 2 == 1));
-			print_square(above_bits[col]);
-		}
+		/* each square in each successive row is derived from the square above it. the row bits
+		 * represent whether there's a stitch between the two squares. if there's a stitch, the
+		 * squares are different, otherwise they are the same. */
+		above_bits
+			.iter_mut()
+			.zip(alt_bits.iter())
+			.for_each(|(x1, &x2)| {
+				*x1 ^= x2 ^ row_bits[row];
+				print_square(*x1);
+			});
+
 		println!();
 	}
 }