His favorite area remained the polder between Groet, the Hondsbosse sea dyke and Zijpersluis, where forests, dunes, beach and sea dyke meet. There were trips to Brittany and Greece, as well as wandering trips by boat in Holland but the focus of his artistic adventure remained the polder near Groet.

During the opening of one of his few exhibitions a speaker praised and explained this work.

Thijs commented afterwards that the speaker had expressed in a few minutes where he, as an artist had been searching for all his life.

Thijs Sterk was a modest man and he was aware of his unachievable goal. The health problems he had later in life, especially with his eyes made it more difficult for him to observe the light.

Painting became almost impossible. It is very moving that on his last drawing, besides a self-portrait, there are also studies of his eyes.

Woodcut
Even now, when I walk through the polder of Groet, I also observe through his eyes. I have seen the creation of quite a number of his paintings here. They have remained close friends.