I am trying organize a complicated class schedule for instructors. There are multiple types of classes T1, T2, T3 Each with their own schedule (see below). I have a spreadsheet that lists all of the days of the year across the top starting with column E. In the next row I indicate the Type in column C, and the Start Date in the column D. I need a formula that looks at the Type, looks at Start Date and places an X in the days whene the class is in session.

T1 = Mon-Sat for 16 weeks, every other week (Mon thru Sat On, Sun thru Sun Off, Repeat for 9 weeks)
T2 = Mon-Thu for 20 weeks
T3 = Mon-Fri for 2 weeks

Any Idea how to write this?

Could you post an example workbook showing what you want it to look like AFTER?