by michael.jones:

The language definition for array types allows array of array to any depth 
and the array indexing operator [] works likewise. However this implication 
is never stated explicitly in the tutorial, overview, examples, FAQ, etc. Why 
not add a specific observation about it or an example like...

package main
import fmt "fmt"

func main() {
    var a1 [2] int;
    a1[1] = 1;
    fmt.Printf("1D array: %v\n\n", a1);

    var a2 [2][2] int;
    a2[1][1] = 2;
    fmt.Printf("2D array: %v\n\n", a2);

    var a3 [2][2][2] int;
    a3[1][1][1] = 3;
    fmt.Printf("3D array: %v\n\n", a3);
}

...somewhere to make the point plain. This is made all the more relevant by 
the hilbert.go test, with its goofy "at()" and "set()" functions,
which seem 
like they are hiding an underlying language disability with respect to 2D 
arrays.  Ahem... not to mention their reliance on assert()  ;-)