Many K-12 CS teachers in Ontario are very familiar with the Don Mills Online Judge (dmoj.ca) site for students to practice their competitive coding skills. A recent book entitled Learn to Code (written be Daniel Zingaro – Associate Professor Teaching Stream at the University of Toronto) combines theory and practice. He explores coding problems in each chapter and then provides a list of similar challenges available on dmoj to further develop your skills
I have been using many of his referenced coding problems with my Grade 11 computer science students this year. These problems don’t include graphics or other Python extensions, but they provide a solid platform to develop introductory skills in the language. Students can extend their fun by explore Pygame Zero or other frameworks/libraries.