diff --git a/src/map-matrix/map-matrix.js b/src/map-matrix/map-matrix.js
index cfddc68..be64687 100644
--- a/src/map-matrix/map-matrix.js
+++ b/src/map-matrix/map-matrix.js
@@ -1,17 +1,14 @@
 import { pipe } from "../pipe/pipe"
 
-const _mapMatrix = (fn, source) => {
+const _mapMatrix = (_fn, source) => {
   const result = []
+  const fn = Array.isArray(_fn) ? pipe(..._fn) : _fn
 
   for (let i = 0, rowCount = source.length; i < rowCount; ++i) {
     const row = []
 
     for (let j = 0, columnCount = source[i].length; j < columnCount; ++j) {
-      row.push(
-        Array.isArray(fn)
-          ? pipe(...fn)(source[i][j])
-          : fn(source[i][j], i, j, source)
-      )
+      row.push(fn(source[i][j], i, j, source))
     }
 
     result.push(row)
@@ -22,16 +19,18 @@ const _mapMatrix = (fn, source) => {
 
 /**
  * Matrix version of "map". Iterates over a two-dimensional array and applies
- * a function on each element, returning a new matrix with the transformed elements.
+ * a function on each element, returning a new matrix with the transformed
+ * elements.
  *
- * @param  {Fn|Fn[]} fn     Transform function called on all elements
- * @param  {[][]}    source Two-dimensional array to iterate over
+ * @param {Fn|Fn[]} fn     Transform function called on all elements
+ * @param {[][]}    source Two-dimensional array to iterate over
  *
+ * @name mapMatrix
  * @tag Array
  * @signature (fn: Fn|Fn[]) => (source: [][]) => [][]
  * @signature (fn: Fn|Fn[], source: [][]) => [][]
  *
- * @return {[][]} Returns new instance
+ * @return {[][]} New array instance
  *
  * @example
  * const inc = x => x + 1
@@ -43,21 +42,11 @@ const _mapMatrix = (fn, source) => {
  * // => [[3, 4], [5, 6]]
  */
 export const mapMatrix = (...params) => {
-  /*
-   * @signature (fn:Fn|Fn[]) => (source: [][]): [][]
-   *
-   * mapMatrix(inc)([[1, 2], [3, 4]])
-   * // => [[2, 3], [4, 5]]
-   */
-  if (params.length === 1) {
+  // @signature (fn) => (source)
+  if (params.length <= 1) {
     return source => _mapMatrix(params[0], source)
   }
 
-  /*
-   * @signature (fn: Fn|Fn[], source: [][]): [][]
-   *
-   * mapMatrix(inc, [[1, 2], [3, 4]])
-   * // => [[2, 3], [4, 5]]
-   */
+  // @signature (fn, source)
   return _mapMatrix(...params)
 }
diff --git a/src/map-matrix/map-matrix.test.js b/src/map-matrix/map-matrix.test.js
index 34d5ff7..bce4c01 100644
--- a/src/map-matrix/map-matrix.test.js
+++ b/src/map-matrix/map-matrix.test.js
@@ -44,5 +44,16 @@ test("mapMatrix", t => {
     ],
     "Multiple transform functions ([square, inc], [[1, 2], [3, 4]]) // => [[2, 5], [10, 17]]"
   )
+
+  mapMatrix((currentValue, rowIndex, columIndex, array) => {
+    t.equal(
+      currentValue,
+      array[rowIndex][columIndex],
+      `callback element "${currentValue}" should equal [${array}][${rowIndex}][${columIndex}]`
+    )
+
+    return currentValue * currentValue
+  })([[1, 2]])
+
   t.end()
 })