Left top - A textbook picture of a human heart
Left middle - Around that a red outline is drawn to get the heart shape
Left bottom - Even though people use dots to create the hridayakamalam, it is only approximate. What one does is - take the outline, successively rotate by 135 degrees and join. When eight of these are joined we come back to the starting motif (135 deg x = 8 = 1080 deg = 360 deg x 3). This is the mathematics behind such patterns.
Right - A hridayakamalam created in such a way with a lamp at the centre is shown.
Enjoy! Regards! - mOhana