I had fun with this guy, but creating the plaid for his trousers was tedious. I'm grateful that his original run was in black and white. Maybe someday soon I'll learn how to make that repeating pattern as a swatch so the computer can do it for me. I'm sure that's a thing.
For those who like my sketches or have no idea on whom I based this illustration, here's my pencil doodle and the primary reference screenshot (copyright of BBC). Yes, the photo is in color, but Troughton revived his role for several episodes during later years.