Sentence:  My windowsill pebble trays are, for the most part, dimestore plastic drawer dividers; some have pebbles in them, others not, but all are filled with water and surmounted with rubberized sink racks or plastic <WSD>egg crating</WSD> which hold the pots. 
Meaning of the word marked with <WSD> tags:  (egg-crating) (plastic mat)