Example 1:

Player A:
★★★
★★★
★★★
★★★
★★★★★

Player B:
★★★
★★★
★★★
★★★
★★★★★

Both players have top level decks. A card of ★★★ can be swapped with another card of ★★★ . Alternatively, both ★★★★★ cards are swapped.


Example 2:

Player A:
★★★
★★★
★★★
★★★
★★★★

Player B:
★★★
★★★
★★★
★★★
★★★★★

A card of ★★★ can be swapped with another card of ★★★ . But the ★★★★ card and ★★★★★ are of different values, and so are excluded from options to be swapped.