He explained it so clearly....angles and vectors and so on....I'm pretty good at mathematics but once he got onto the variables he lost me completely....
"Yes I'm sure it's all good in theory.....but does it work in the real world?"
"Oh yes Sissy, let me show you.....just tilt your head back and open your mouth....it'll all be clear in just a minute!!!"
And he was right....this was something I could really wrap my head around!!!!