What are three important events that led to Nick's big idea in Frindle?

Three things happened on the day that Nick Allen got his big idea.  

The first thing happened while Nick and his friend, Janet, were walking home from school.  They usually took the bus, but had stayed late at school for a meeting.  During their walk, Janet spotted a gold ballpoint pen on the ground.  

The second thing that happened during their walk was that Nick recalled what Mrs. Granger, his teacher, had told him earlier that day.  She explained to him that words were given meaning by people.  

While Nick was lost in his thoughts, he bumped into Janet.  This caused the pen they found to fall out of her hand and onto the ground.  Nick picked it up to hand it to Janet.  He spoke, but then hesitated.  "Here's your... frindle," he said to her.  From then on, Nick called pens "frindles."