Tantra Sāra 1.010
śāntasaṁvit ṣaḍguṇaśca sārātmā haṁsalālukau। pañcāśanmūrtayastvētā mamākārādalikṣakāḥ ॥10॥
sha - for Shāntasaṁvit, ṣha - for Shadgunah, sa - for Sārātmā, ha - for Hansah, and la - for Lālukah. Thus are the fifty forms of the lord deciphered from the alphabets.
Note:
Shāntasaṁvit = one who possesses peace, Shadgunah = one who has six auspicious qualities, i.e. wealth, valour, fame, virtue, knowledge, scientific knowledge; Sārātmā = the essence of the essence, Hansah = he who knows the essence of everything, and Lālukah = one who grants happiness to the liberated.
A pictorial representation of how everything is derived from the Pranava, 'Om':
