We bought a new bed for the cats recently, a wicker double-decker with a bed on top and a cosy little hidey-hole below.
As predicted, Patch, the scaredy-cat of the group, quickly claimed the cave for herself (good choice, I thought: a naturally defensible position). She's occasionally had to defend it from Twinkle, who's grown quite aggressive recently (it seems everytime we turn our head she's in a running fight with Iffy, with her doing the chasing). Twinkle's such a bully that the only way Patch can engage her on equal terms is (as you can see from the photo) from the security of her little cave, with her body and head safely tucked in, and only the paw exposed.
Rough play, but it's a bloodless fight though: the cats leave their claws in, and swat at each other like boxers (Twinkle once swatted Iffy so hard I heard the "thwack" from across the room), and are otherwise on good terms.