The initial guidelines are as follows. All teams must include at least one programmer. Further, any team of size 3 must include one non-programmer, and any team of size 4 must include two non-programmers.
By the end of the day (11:59PM) Wednesday, April 14, teams should write to the TA (vrastogi AT u DOT northwestern DOT edu) saying who is on the team, and identifying each team member as a programmer or non-programmer. If you can't find a team, write the TA ASAP (say whether you're a programmer or non-programmer), and you'll be put in touch with other students looking for a team.