Aaaand once again Gary Kildall gets left out of history. While CEO of Digital Research, the largest software company in the world at the time (besides IBM), he did an entire implementation himself! DR Logo had some innovative graphical features.
Gary Killdall tried to buy Terrapin. It was unfavorable terms and I didn't agree. He went away mad and wrote something in C an implementation of what looked like Logo but I don't know how he choose to implement it. I remember him talking about structs of various sorts at one point, instead of using lists so I assume he was concerned about efficiency. I never had a discussion with them about their interest in pedagogy so I can't comment.