This article compares two examples of student work on an assignment requiring undergraduates to engage with primary source material in a course on the history of mathematics. In the first example, the student delved into Alan Turing’s unpublished work on phyllotaxis to write an interesting paper, but did not apply Turing's mathematics beyond its initial scope. Conversely, in the second example, the student extended a number theory paper of Leonhard Euler, but was not interested in the material. Strengths and weaknesses of each student’s work are considered, leading to a discussion of concrete ways to improve the assignment in the future, in order to lead students to think deeply about primary mathematical sources that they themselves find interesting.