This is the part of the obituary that I found the most powerful:

Though inventing filled his working hours, Mr. Gundlach was enthralled with canoeing, hiking, skiing — activities he pursued avidly most of his lifetime. When he was in his 50s, feeling the need for a new hobby, he took up windsurfing. He also made sure to be home from work in time to play ball or build a bicycle jump, his children recalled.

“He had what we would call today a work-life balance,” said Eric Gundlach. “He was the kind of man who left work behind.”