Counting and Rhyming

     Several days ago my email contained a surprise message -- containing a mathy poem --  from Ramandeep Johal, a theoretical physicist at IISER Mohali (Indian Institute of Science Education and Research) in northern India.  I offer Johal's poem below -- a poem from his 2016 collection, The Sea of Tranquility 

     From One to Ten     by Ramandeep Johal

          Some things you find in pairs
          some exist just alone.
          While a trinity needs
          some degree of unity,
          a group of four
          requires bit more.

Colorful mathematics for your smartphone

     "Bhaskara II (1114-1185) was an Indian mathematician and astronomer. He composed the Siddhanta Siromani, a treatise in four parts -- Lilavati (basics), Bijaganita (algebra), Grahaganita (planetary motion) and Goladhyaya (spheres)."
     This quotation comes from an early page of a new (2015) graphic e-book entitled The Illustrated Lilavati -- the text is based on a 1816 John Taylor translation, edited and illustrated for lilboox by Somdip Datta and available for download on smartphones and other devices.  Lilavati (named for the daughter of Bhaskara) was written in 1150 and was a standard textbook for arithmetic in India for many years.
     This e-book contains 25 illustrated problems (and solutions); here is the first: