I wasn't sure if these ugnim are on the top or bottom of the kupah. Rashi said they are "b'makom" the shulayim, so I didn't know if that meant in their location (i.e. bottom) or instead of (and maybe it means the top). I ask because if they are on the bottom, so once the gemara says that fruits are different than water beacuse by fruits you turn the kupah over completely, so wouldn't the sheretz fall out even if it had a shulayim? In which case shouldn't the taharos be tahor (which is against Hillel/Shammai that it's tamei)?

Thank you.