This paper reports on a collective case study of three blended courses taught by different instructors in a higher education institution, with the purpose of identifying the different types of blend and how the blend supports student learning. Based on the instructors' and students' interviews, and document analysis of course outlines, two major principles, consolidation and extension, differentiating the design of the three courses, are identified. The consolidation principle emphasises designing different types of activities for students to think again, so that their knowledge can be consolidated. The extension principle emphasises the extension of the space of learning and catering the diverse needs of students. There are also design principles commonly found, with the emphases on student autonomy, interaction and feedback, and the awareness of student diversity. The findings contribute to the design of blended learning, especially on how the face-to-face and online components can be combined.