Spatial reasoning--the ability to visualise and play with shapes in one's mind--is essential in many fields, and crucial in any Science, Technology, Engineering, Mathematics [STEM] discipline. It is, for example, the ability that the engineer needs to build bridges; the chemist to see the three-dimensional structure of a molecule; the architect to design buildings; and the doctor to navigate the patient's abdominal cavity with a laparoscope. Spatial thinking is an important factor for achievement in areas of STEM. While there is evidence of a gender gap in this area, there is also evidence that these reasoning skills can be improved with practice. The author of this article teaches in an all-girls school, and wished to address both the spatial reasoning and coding gap by creating a brief unit on that subject matter. The unit described in this article was designed to simultaneously introduce the author's students to a beginner level of computer programming, and assist them in developing and practice their spatial skills.