Representing a lake or pool. Compare the Chinese character 𣶒. Detailed Old Kingdom forms cover the interior with vertical zigzags of green or blue rippling water:
(𓈜). A form with a few diagonal lines across the interior
(𓈚) appeared in hieratic and semi-cursive hieroglyphs during the Old Kingdom but rarely appeared in hieroglyphs proper before the Late Period. Another variant adds lines, perhaps to suggest depth:
(𓈛). In general, the outline and ripples of the glyph are usually colored black or dark blue, the water green or lighter blue (compare the canal glyph 𓈘 and the ripple glyph 𓈖). The phonogrammatic value of š is derived by the rebus principle from its use as a logogram for š(“pool, lake”).
(𓊌) are extremely similar. The stone hieroglyph is often drawn shorter/squatter than the pool hieroglyph to distinguish the two. In some inscriptions they could also be distinguished by color: the sides of the pool glyph were blue and the interior water was green, while the stone glyph was often white, although sometimes the stone glyph was colored blue instead, see its entry for more.
Gardiner, Alan (1957) Egyptian Grammar: Being an Introduction to the Study of Hieroglyphs, third edition, Oxford: Griffith Institute, →ISBN, page 491
Henry George Fischer (1988) Ancient Egyptian Calligraphy: A Beginner’s Guide to Writing Hieroglyphs, New York: Metropolitan Museum of Art, →ISBN, page 13
Betrò, Maria Carmela (1995) Geroglifici: 580 Segni per Capire l'Antico Egitto, Milan: Arnoldo Mondadori Editore S.p.A., →ISBN
Peust, Carsten (1999) Egyptian Phonology: An Introduction to the Phonology of a Dead Language[1], Göttingen: Peust und Gutschmidt Verlag GbR, page 48
