I knew Mark for more than 46 years. He was a kind and gentle person. He had many talents and interests. He was as a mutual friend called him a Renaissance man. He excelled in his water paintings. He had a passion for music, ranging from classical music to rock and roll. He loved science and mathematics of which he taught himself many of their applications. We would often sing together, "Give me a ticket for an airplane," by Joe Cocker. I am happy that I saved his last four or five voicemails to me; the voicemails consist of Mark singing the first few lines of the mentioned song. My heart is breaking thinking about it. Mark was always ready to help a friend in need. I was blessed by his friendship. I will miss him terribly.