In Spring 2021 6.857 will be offered in an online format. There will be no on-campus element to the course. Lectures, recitations, office hours, and project presentations will all be zoom-based. Lectures will generally be recorded and posted in a folder on the class website that is accessible only to registered students and listeners. Other course materials will be posted on the class website as in previous years. Lecture attendance is not required, nor is participation noted (with the exception of attendance for project presentation by all teams of the class).