doc: 2d array example (#6058)

doc/docs.md

@@ -524,6 +524,24 @@ println(upper) // ['HELLO', 'WORLD']
 
 `it` is a builtin variable which refers to element currently being processed in filter/map methods.
 
+#### Multidimensional Arrays
+
+Arrays can have more than one dimension.
+
+2d array example:
+```v
+mut a := [][]int{len:2, init: []int{len:3}}
+a[0][1] = 2
+println(a) // [[0, 2, 0], [0, 0, 0]]
+```
+
+3d array example:
+```v
+mut a := [][][]int{len:2, init: [][]int{len:3, init: []int{len:2}}}
+a[0][1][1] = 2
+println(a) // [[[0, 0], [0, 2], [0, 0]], [[0, 0], [0, 0], [0, 0]]]
+```
+
 ### Maps
 
 ```v