Knock knock

I was at a doctors appointment unrelated to Parkinson and the doctor greeted me along with an intern. I took my seat in a chair and there was chair next to it which I rested my arm on it my tremor was going a mile a minute but I tuned it out because I'm used to it. There was a knock on the door and the doctor promptly stopped what he was doing to look out to see who was there and there was no one in the hallway he sat down befuddled. He continue on with my examination then there it was again knock knock knock knock knock knock the intern this time went to the door and there was no one there. Couple of minutes later knock knock knock knock there it was again. He opened up the door and said who is it to his dismay there was no one there. Then I realized it was me who was causing the knock my arm was hitting the chair in a rhythmic motion causing the knock knock knock knock when I think about it I can control the tremor but I let it go one more time just to see if the expression on his face before I let him off the hook and apologized.😀😀😀 he was a good sport and saw the humor and laughed with me.