Saying the letter O,T,P, I

Richie's latest in the series is saying the letters O, T , I and P. Where ever we go, whether it is shopping mall, tourist spot, TV etc, he recognises those letters and shouts out loud. :) He knows Pooh, peas, start with P. When he sees T he starts "grrrooooow , groooowwww" meaning T for tiger. He can also draw O and tries some straight lines to draw T and I.