Yellu is the Tamil name for sesame seed (Till in Hindi)Till is rich in manganese,calcium ,copper Vitamin B,E and anti oxidants.They are also said to be good for cholesterol.
Women of ancient Babylon would eat halva, a mixture of honey and sesame seeds to prolong youth and beauty, while Roman soldiers ate the mixture for strength and energy(http://en.wikipedia.org/wiki/Sesame_seed )Sesame oil is also used as medicine in Siddha and Ayurveda.
Till balls are very easy and quick to make.Jaggery , which is used to make these sweet balls are also considered very healthy.In Tamilnadu during early pregnancy they avoid this sweet.
Jaggery- according to taste
1)Dry fry sesame seed till nice aroma comes.
2)Grate jaggery and powder it with fried sesame seed.