Egyptians made houses out of mudbricks and cooked outside to keep the interior cool. They told time using water clocks, where water flowed between pots to mark the hours, and sundials, though water clocks needed frequent refilling. Egyptians also built elaborate pyramids using levers and ramps to move heavy stones. They wore linen clothes made from flax plant fibers and some wore wigs, with the wealthy adorning themselves with jewelry as well. Egyptian society was highly stratified with the pharaoh as absolute ruler above priests, citizens, and peasants.