I really like this. But one minor quibble - siesta kind of gives the game away. The fragment bit could be slightly different. On the other hand, the phrase is simply brilliant!
Siesta does seem redundant in the haiga, but the word just sounded catchy and then stayed...now for alternatives... stilltwo pairs of legs rest side by side zzzzz...two pairs of legs rest side by sidesnore...two pairs of legs rest side by side