Wikipedia
Nāṉmaṇikkaṭikai is a Tamil poetic work of didactic nature belonging to the Patiṉeṇkīḻkaṇakku anthology of Tamil literature. This belongs to the 'post Sangam period corresponding to between 100 – 500 CE. Nanmanikkatigai contains one hundred songs written by the poet Vilambi Naganaar. This poetic work is famous for its clarity and easy readability and is often a prescribed text for schools in Tamil Nadu. The poems of Nanmanikkatigai are written in the Venpa meter.
The poems of Nāṉmaṇikkaṭikai each contain four different ideas. The name Nāṉmaṇikkaṭikai denotes this fact comparing the four ideas to four well-chosen gems adorning each poem. The following poem describes four different groups of people who cannot sleep well at night, namely, a person who has committed a crime (a thief, robber, murderer, etc.), a lovelorn person, someone who hankers after money and a miser who worries about losing his money:
கள்வம்என் பார்க்கு துயில் இல்லை, காதலிமாட்டு
உள்ளம்வைப்பார்க்கும் துயில் இல்லை, ஒண்பொருள்
செய்வம்என் பார்க்கும் துயில் இல்லை, அப்பொருள்
காப்பார்க்கும் இல்லை துயில்.