$hash{a}{drinks}=1; 
$hash{b}{drinks}=2;

##</code><code>##

+-------+     +----------+    +-----------+    +-------------+
| %hash | +-->| Anon Ref | +->| Anon hash | +->| Anon scalar |
+-------+ |   +----------+ |  +-----------+ |  +-------------+
| a   ----+   | addr   ----+  | drinks  ----+  | 1           |
| b   -----+  +----------+    +-----------+    +-------------+
+-------+  |
           |  +----------+    +-----------+    +-------------+
           +->| Anon Ref | +->| Anon hash | +->| Anon scalar |
              +----------+ |  +-----------+ |  +-------------+
              | addr   ----+  | drinks  ----+  | 2           |
              +----------+    +-----------+    +-------------+

##</code><code>##

>perl -e"$h{a}{d}=1; $h{b}{d}=2; print qq{$_: $h{$_}\n} for keys %h;"
a: HASH(0x22534c)
b: HASH(0x2253a0)

##</code><code>##

+-------+     +----------+         +-----------+    +-------------+
| %hash | +-->| Anon Ref |  +----->| Anon hash | +->| Anon scalar |
+-------+ |   +----------+  |      +-----------+ |  +-------------+
| a   ----+   | addr   -----+      | drinks  ----+  | 1           |
| b   -----+  +----------+  |      +-----------+    +-------------+
+-------+  |                |
           |  +----------+  |      +-----------+    +-------------+
           +->| Anon Ref |  |  +-->| Anon hash | +->| Anon scalar |
              +----------+  |  |   +-----------+ |  +-------------+
              | addr   --------+   | drinks  ----+  | 2           |
              +----------+  |  |   +-----------+    +-------------+
                            |  |
+-------+     +NEW-------+  |  |
| %copy | +-->| Anon Ref |  |  |
+-------+ |   +----------+  |  |
| a   ----+   | addr   -----+  |
| b   -----+  +----------+     |
+-------+  |                   |
           |  +NEW-------+     |
           +->| Anon Ref |     |
              +----------+     |
              | addr   --------+
              +----------+

##</code><code>##

+-------+     +----------+    +-----------+    +-------------+
| %hash | +-->| Anon Ref | +->| Anon hash | +->| Anon scalar |
+-------+ |   +----------+ |  +-----------+ |  +-------------+
| a   ----+   | addr   ----+  | drinks  ----+  | 1           |
| b   -----+  +----------+    +-----------+    +-------------+
+-------+  |
           |  +----------+    +-----------+    +-------------+
           +->| Anon Ref | +->| Anon hash | +->| Anon scalar |
              +----------+ |  +-----------+ |  +-------------+
              | addr   ----+  | drinks  ----+  | 2           |
              +----------+    +-----------+    +-------------+

+-------+     +NEW-------+    +NEW--------+    +NEW----------+
| %copy | +-->| Anon Ref | +->| Anon hash | +->| Anon scalar |
+-------+ |   +----------+ |  +-----------+ |  +-------------+
| a   ----+   | addr   ----+  | drinks  ----+  | 1           |
| b   -----+  +----------+    +-----------+    +-------------+
+-------+  |
           |  +NEW ------+    +NEW--------+    +NEW----------+
           +->| Anon Ref | +->| Anon hash | +->| Anon scalar |
              +----------+ |  +-----------+ |  +-------------+
              | addr   ----+  | drinks  ----+  | 2           |
              +----------+    +-----------+    +-------------+