kAma kalA

Source: here.

mukhaM binduM kR^itvA kucha yugam-adhas-tasya tadadho hakArArdhaM dhAyed yo hara-mahiShi te manmatha-kalAM |

sa sadyaH saMkShobhaM nayati vanitA ity-ati-laghu trilokIm apy-Ashu bhramayati ravIndu-stana-yugAM ||

Making the bindu to be the face, what is beneath to be the breasts, and what is still underneath one half of the syllable ha, one meditates on your manmatha kalA, oh she queen of hara.
One who does so very easily excites girls; he very soon bewitches the Triple-world with the sun and moon as her breasts.

The realization of kAmakalA follows from the bijas of the yantra associated with the mantra: 4 hrIMs enclosed in a circle.

The mAya bIja forms thus:

1. Im- the gupta mahAsArasvata bIja which has the bindu forming the face and the two semi-circular curves the breasts.
2. r- the consonant of fire from the 3rd eye on the forehead.
3. h- the hakArardhaM, the lower half of ha which is equivalent of the yoni vowel e. Thus it is the yoni, the root of the manmatha kalA.