Why is x[0] != x[0][0] != x[0][0][0]?

x is a pointer to an array of 5 pointers to int.
x[0] is an array of 5 pointers to int.
x[0][0] is a pointer to an int.
x[0][0][0] is an int.

                       x[0]
   Pointer to array  +------+                                 x[0][0][0]         
x -----------------> |      |         Pointer to int           +-------+
               0x500 | 0x100| x[0][0]---------------->   0x100 |  10   |
x is a pointer to    |      |                                  +-------+
an array of 5        +------+                        
pointers to int      |      |         Pointer to int                             
               0x504 | 0x222| x[0][1]---------------->   0x222                    
                     |      |                                             
                     +------+                                             
                     |      |         Pointer to int                              
               0x508 | 0x001| x[0][2]---------------->   0x001                    
                     |      |                                             
                     +------+                                             
                     |      |         Pointer to int                              
               0x50C | 0x123| x[0][3]---------------->   0x123                    
                     |      |                                             
                     +------+                                             
                     |      |         Pointer to int                              
               0x510 | 0x000| x[0][4]---------------->   0x000                    
                     |      |                                             
                     +------+                                             

You can see that

• x[0] is an array and will converted to pointer to its first element when used in an expression (with some exceptions). Therefore x[0] will give the address of its first element x[0][0] which is 0x500.
• x[0][0] contains address of an int which is 0x100.
• x[0][0][0] contains an int value of 10.

So, x[0] is equal to &x[0][0]and therefore, &x[0][0] != x[0][0].
Hence, x[0] != x[0][0] != x[0][0][0].