Explain behaviour when appending to a slice containing other slices

content/en/functions/append.md

@@ -26,4 +26,12 @@ The same example appending a slice to a slice:
 {{ $s = $s | append (slice "d" "e") }}
 ```
 
+If a slice contains other slices, further slices will be appended as values:
+
+```go-html-template
+{{ $s := slice (slice "a" "b") (slice "c" "d") }}
+{{ $s = $s | append (slice "e" "f") (slice "g" "h") }}
+{{/* $s now contains a [][]string containing four slices:  ["a" "b"],  ["c" "d"], ["e" "f"], and ["g" "h"] */}}
+```
+
 The `append` function works for all types, including `Pages`.

content/en/functions/scratch.md

@@ -72,7 +72,7 @@ Get the value of a given key.
 
 Add a given value to existing value(s) of the given key.
 
-For single values, `Add` accepts values that support Go's `+` operator. If the first `Add` for a key is an array or slice, the following adds will be appended to that list.
+For single values, `Add` accepts values that support Go's `+` operator. If the first `Add` for a key is an array or slice, the following adds will be [appended](/functions/append/) to that list.
 
 ```go-html-template
 {{ $scratch.Add "greetings" "Hello" }}