Improve readability

contracts/utils/math/Math.sol

@@ -229,16 +229,44 @@ library Math {
     function invMod(uint256 a, uint256 n) internal pure returns (uint256) {
         unchecked {
             if (n == 0) return 0;
-            uint256 r1 = a % n;
-            uint256 r2 = n;
-            int256 t1 = 0;
-            int256 t2 = 1;
-            while (r1 != 0) {
-                uint256 q = r2 / r1;
-                (t1, t2, r2, r1) = (t2, t1 - t2 * int256(q), r1, r2 - r1 * q);
+
+            // The inverse modulo is calculated using the Extended Euclidean Algorithm (iterative version)
+            // Used to compute integers x and y such that: ax + ny = gcd(a, n).
+            // When the gcd is 1, then the inverse of a modulo n exists and it's x.
+            // ax + ny = 1
+            // ax = 1 + (-y)n
+            // ax ≡ 1 (mod n) # x is the inverse of a modulo n
+
+            // If the remainder is 0 the gcd is n right away.
+            uint256 remainder = a % n;
+            uint256 gcd = n;
+
+            // Therefore the initial coefficients are:
+            // ax + ny = gcd(a, n) = n
+            // 0a + 1n = n
+            int256 x = 0;
+            int256 y = 1;
+
+            while (remainder != 0) {
+                uint256 quotient = gcd / remainder;
+
+                (gcd, remainder) = (
+                    // The old remainder is the next gcd to try.
+                    remainder,
+                    // Compute the next remainder.
+                    gcd - remainder * quotient
+                );
+
+                (x, y) = (
+                    // Increment the coefficient of a.
+                    y,
+                    // Decrement the coefficient of n.
+                    x - y * int256(quotient)
+                );
             }
-            if (r2 != 1) return 0;
-            return t1 < 0 ? (n - uint256(-t1)) : uint256(t1);
+
+            if (gcd != 1) return 0; // No inverse exists.
+            return x < 0 ? (n - uint256(-x)) : uint256(x); // Wrap the result if it's negative.
         }
     }