diff --git a/4dev/tests/Convert/CoreLibsConvertMathTest.php b/4dev/tests/Convert/CoreLibsConvertMathTest.php
index 95002850..6441ca79 100644
--- a/4dev/tests/Convert/CoreLibsConvertMathTest.php
+++ b/4dev/tests/Convert/CoreLibsConvertMathTest.php
@@ -156,12 +156,32 @@ final class CoreLibsConvertMathTest extends TestCase
 	public function providerMultiplyMatrices(): array
 	{
 		return  [
-			'single' => [
+			'[3] x [3] => [3x1]' => [
 				[1, 2, 3],
 				[1, 2, 3],
 				[14]
 			],
-			'double first' => [
+			'[3] x [3x1]' => [
+				[1, 2, 3],
+				[[1], [2], [3]],
+				[14]
+			],
+			'[3] x [3x1]' => [
+				[1, 2, 3],
+				[[1], [2], [3]],
+				[14]
+			],
+			'[1x3L] x [3x1]' => [
+				[[1, 2, 3]],
+				[[1], [2], [3]],
+				[14]
+			],
+			'[1x3] x [3x1]' => [
+				[[1], [2], [3]],
+				[[1], [2], [3]],
+				[1, 2, 3]
+			],
+			'[2x3] x [3] => [3x1]' => [
 				[
 					[1, 2, 3],
 					[1, 2, 3]
@@ -172,7 +192,18 @@ final class CoreLibsConvertMathTest extends TestCase
 					14
 				]
 			],
-			'double both' => [
+			'[2x3] x [3x1]' => [
+				[
+					[1, 2, 3],
+					[1, 2, 3]
+				],
+				[[1], [2], [3]],
+				[
+					14,
+					14
+				]
+			],
+			'[2x3] x [2x3] => [3x3]' => [
 				[
 					[1, 2, 3],
 					[1, 2, 3],
@@ -186,7 +217,37 @@ final class CoreLibsConvertMathTest extends TestCase
 					[3, 6, 9]
 				]
 			],
-			'tripple first, single second' => [
+			'[2x3] x [3x3]' => [
+				[
+					[1, 2, 3],
+					[1, 2, 3],
+				],
+				[
+					[1, 2, 3],
+					[1, 2, 3],
+					[0, 0, 0],
+				],
+				[
+					[3, 6, 9],
+					[3, 6, 9]
+				]
+			],
+			'[2x3] x [3x2]' => [
+				'a' => [
+					[1, 2, 3],
+					[1, 2, 3],
+				],
+				'b' => [
+					[1, 1],
+					[2, 2],
+					[3, 3],
+				],
+				'prod' => [
+					[14, 14],
+					[14, 14],
+				]
+			],
+			'[3x3] x [3] => [1x3]' => [
 				[
 					[1, 2, 3],
 					[1, 2, 3],
@@ -199,7 +260,7 @@ final class CoreLibsConvertMathTest extends TestCase
 					14
 				]
 			],
-			'tripple first, double second' => [
+			'[3x3] x [2x3] => [3x3]' => [
 				[
 					[1, 2, 3],
 					[1, 2, 3],
@@ -215,7 +276,24 @@ final class CoreLibsConvertMathTest extends TestCase
 					[3, 6, 9],
 				]
 			],
-			'single first, tripple second' => [
+			'[3x3] x [3x3]' => [
+				[
+					[1, 2, 3],
+					[1, 2, 3],
+					[1, 2, 3],
+				],
+				[
+					[1, 2, 3],
+					[1, 2, 3],
+					// [0, 0, 0],
+				],
+				[
+					[3, 6, 9],
+					[3, 6, 9],
+					[3, 6, 9],
+				]
+			],
+			'[3] x [3x3]' => [
 				[1, 2, 3],
 				[
 					[1, 2, 3],
@@ -226,7 +304,7 @@ final class CoreLibsConvertMathTest extends TestCase
 					[6, 12, 18],
 				]
 			],
-			'double first, tripple second' => [
+			'[2x3] x [3x3]' => [
 				[
 					[1, 2, 3],
 					[1, 2, 3],
diff --git a/www/lib/CoreLibs/Convert/Math.php b/www/lib/CoreLibs/Convert/Math.php
index a20085f7..41eb7463 100644
--- a/www/lib/CoreLibs/Convert/Math.php
+++ b/www/lib/CoreLibs/Convert/Math.php
@@ -136,6 +136,28 @@ class Math
 	 *
 	 * It returns an array which is the product of the two number matrices passed as parameters.
 	 *
+	 * NOTE:
+	 * if the right side (B matrix) has a missing row, this row will be fillwed with 0 instead of
+	 * throwing an error:
+	 * A:
+	 * [
+	 *   [1, 2, 3],
+	 *   [4, 5, 6],
+	 * ]
+	 * B:
+	 * [
+	 *   [7, 8, 9],
+	 *   [10, 11, 12],
+	 * ]
+	 * The B will get a third row with [0, 0, 0] added to make the multiplication work as it will be
+	 * rewritten as
+	 * B-rewrite:
+	 * [
+	 *   [7, 10, 0],
+	 *   [8, 11, 12],
+	 *   [0, 0, 0] <- automatically added
+	 * ]
+	 *
 	 * @param  array<float|int|array<int|float>> $a m x n matrice
 	 * @param  array<float|int|array<int|float>> $b n x p matrice
 	 *
@@ -161,8 +183,9 @@ class Math
 		$p = count($b[0]);
 
 		// transpose $b:
+		// so that we can multiply row by row
 		$bCols = array_map(
-			callback: fn ($k) => \array_map(
+			callback: fn ($k) => array_map(
 				(fn ($i) => is_array($i) ? $i[$k] : 0),
 				$b,
 			),
@@ -175,7 +198,8 @@ class Math
 					array_reduce(
 						array: $row,
 						callback: fn ($a, $v, $i = null) => $a + $v * (
-							$col[$i ?? array_search($v, $row) ?: 0]
+							// if last entry missing for full copy add a 0 to it
+							$col[$i ?? array_search($v, $row, true)] ?? 0 /** @phpstan-ignore-line */
 						),
 						initial: 0,
 					) :
@@ -191,7 +215,7 @@ class Math
 
 		if ($m === 1) {
 			// Avoid [[a, b, c, ...]]:
-			$product = $product[0];
+			return $product[0];
 		}
 
 		if ($p === 1) {